Thru-tubing retrievable intelligent completion system

FIELD

Embodiments relate generally to well completion systems and more particularly to thru-tubing completion systems.

BACKGROUND

A well generally includes a wellbore (or “borehole”) that is drilled into the earth to provide access to a geographic formation below the earth's surface (often referred to as “subsurface formation”) to facilitate the extraction of natural resources, such as hydrocarbons and water, from the formation, to facilitate the injection of fluids into the formation, or to facilitate the evaluation and monitoring of the formation. In the petroleum industry, wells are often drilled to extract (or “produce”) hydrocarbons, such as oil and gas, from subsurface formations. The term “oil well” is typically used to refer to a well designed to produce oil. In the case of an oil well, some natural gas is typically produced along with oil. A well producing both oil and natural gas is sometimes referred to as an “oil and gas well” or “oil well.”

Developing an oil well typically includes a drilling stage, a completion stage, and a production stage. The drilling stage normally involves drilling a wellbore into a portion of a subsurface formation that is expected to contain a concentration of hydrocarbons that can be produced, often referred to as a “hydrocarbon reservoir” or “reservoir.” The drilling process is usually facilitated by a surface system, including a drilling rig that sits at the earth's surface. The drilling rig can, for example, operate a drill bit to cut the wellbore, hoist, lower and turn drill pipe, tools and other devices in the wellbore (often referred to as “down-hole”), circulate drilling fluids in the wellbore, and generally control various down-hole operations. The completion stage normally involves making the well ready to produce hydrocarbons. In some instances, the completion stage includes installing casing, perforating the casing, installing production tubing, installing down-hole valves for regulating production flow, and pumping fluids into the well to fracture, clean or otherwise prepare the formation and well to produce hydrocarbons. The production stage involves producing hydrocarbons from the reservoir by way of the well. During the production stage, the drilling rig is usually and replaced with a collection of valves at the surface (often referred to as a “production tree”). The production tree is operated in coordination with down-hole valves to regulate pressure in the wellbore, to control production flow from the wellbore and to provide access to the wellbore in the event additional completion work (often referred to as a “workover”) is needed. A pump jack or other mechanism can provide lift that assists in extracting hydrocarbons from the reservoir, especially when the pressure in the well is so low that the hydrocarbons do not flow freely to the surface. Flow from an outlet valve of the production tree is normally connected to a distribution network of midstream facilities, such as tanks, pipelines and transport vehicles that transport the production to downstream facilities, such as refineries and export terminals. In the event a completed well requires workover operations, such as repair of the wellbore or the removal and replacement of down-hole components, a workover rig may need to be installed for use in removing and installing tools, valves, and production tubing.

SUMMARY

Applicants have recognized that traditional well configurations can create complexities with regard various aspects of drilling, completion and production operations. For example, production tubing is normally installed after casing is installed to avoid additional time and costs that would otherwise be involved with workover operations that require removing and reinstalling production tubing. For example, in the case of a workover operation that requires casing of a portion of the wellbore, the workover may involve retrieving installed production tubing installed before a casing operation and, then, re-running the production tubing after the casing operation is complete. Accordingly, it is important for well operators to have thorough plan for completing a well, including completion plans, to avoid potential delays and costs. Unfortunately, wells often experience unpredictable issues, and even a well-designed well plan is susceptible to alterations that can increase time and cost expenditures to develop the well. For example, over time wells can develop flows of undesirable substances, such as water or gas, into the wellbore from the formation (often referred to as “breakthrough”). Breakthrough can result in the unwanted substances inhibiting or mixing with production fluids. For example, water and gas entering at one portion of the wellbore may mix with oil production from an adjacent portion of the wellbore. Breakthrough often occurs in un-cased (or “open-holed”) sections of the wellbore, as there is no substantial barrier to fluid flowing into the wellbore from the formation. Attempted solutions can involve lining the portion of the wellbore to prevent the unwanted substances from entering the wellbore. If a portion of a wellbore is badly damaged, that portion of the wellbore may need to abandoned. This can include sealing off the damaged portion of the wellbore and, if needed, drilling a new wellbore section, such as a lateral, that avoids or otherwise routes around the damaged portion of the wellbore.

Unfortunately, when unforeseen issues with a well occurs, such as breakthrough or other damage, a well operator may have to modify a well plan for the well. This can include engaging in costly workover operations in an attempt to resolve the issue. For example, if casing is required to line a portion of the wellbore to remedy a breakthrough issue, the well operator may need to remove already installed production tubing, valves and tools from the wellbore, perform the casing operation to repair the wellbore, and finally reinstall the production tubing valves and tools in the wellbore. This can increase costs by way of the cost to perform the workover operations, as well as revenue losses associated with the lost production over the timespan of the workover operation. Unfortunately, these types of issue can arise over time, and are even more common with older existing wells. Thus, it is important to provide workover solutions that can effectively resolve these types of issues with minimal impact on a well plan, in effect helping to reduce costs or delays that are traditionally associated with workover operations and improve the net profitability of the well.

Recognizing these and other shortcomings of existing systems, Applicants have developed novel systems and methods of operating a well using a thru-tubing completion system (TTCS) employing subsurface completion units (SCUs). In some embodiments, a TTCS includes one or more SCUs that are deployed down-hole, in a wellbore having a production tubing string in place. For example, a SCU may be delivered through the production tubing to a target zone of the wellbore in need of completion, such as an open-holed portion of the wellbore that is down-hole from a down-hole end of the production tubing and that is experiencing breakthrough. In some embodiments, a deployed SCU is operated to provide completion of an associated target zone of the wellbore. For example, seals and valves of a deployed SCU may be operated to provide providing zonal fluid isolation of annular regions of the wellbore located around the SCU, to control the flow of breakthrough fluids into a stream of production fluids flowing up the wellbore and the production tubing.

In some embodiments, a SCU includes a modular SCU formed of one or more SCU modules (SCUMs). For example, multiple SCUMs may be stacked in series, end-to-end, to form a relatively long SCU that can provide completion of a relatively long section of a wellbore. This can provide additional flexibility as a suitable numbers of SCUMs may be stacked together to provide a desired length of completion in a wellbore. In some embodiments, the SCUMs can be assembled at the surface or down-hole. This can further enhance the flexibility of the system by reducing the number of down-hole runs needed to install the SCUs, by providing flexibility in the physical size of the SCU to be run through the production tubing and the wellbore, and by providing flexibility to add or remove SCUMs at a later time, as the well evolves over time. The ability to run the SCUs through the production tubing can enable the SCUs to provide completion functions, such as lining a wellbore of a well to inhibit breakthrough, without having to remove and re-run the production tubing in the well during installation or retrieval of the SCUs.

Provided in some embodiments is a thru-tubing completion system including a SCU adapted to pass through production tubing disposed in a wellbore of a well, and to be disposed in a target zone of an open-holed portion of the wellbore and perform completion operations in the target zone. The SCU including the following: a SCU wireless transceiver; one or more SCU anchoring seals adapted to be positioned in an un-deployed position and a deployed position (the un-deployed position of the one or more SCU anchoring seals enabling the SCU to pass through the production tubing disposed in the wellbore of the well, and the deployed position of the one or more SCU anchoring seals providing a seal against a wall of the target zone of the open-holed portion of the wellbore to provide zonal isolation between regions in the wellbore); and one or more SCU centralizers adapted to be positioned in an un-deployed position and a deployed position (the un-deployed position of the one or more SCU centralizers enabling the SCU to pass through the production tubing disposed in the wellbore of the well, and the deployed position of the one or more SCU centralizers positioning the SCU in the target zone of the open-holed portion of the wellbore). The system further including a down-hole wireless transceiver adapted to be disposed at a down-hole end of the production tubing in the wellbore of the well, to be communicatively coupled to a surface control system of the well, to communicate wirelessly with the SCU wireless transceiver, and to provide for communication between the SCU wireless transceiver and the surface control system of the well.

In some embodiments, the un-deployed position of the one or more SCU anchoring seals includes the one or more SCU anchoring seals having an outer diameter that is less than an inner diameter of the production tubing, and the deployed position of the one or more SCU anchoring seals includes the one or more SCU anchoring seals having an outer diameter that is equal to or greater than an inner diameter of the wall of the target zone of the open-holed portion of the wellbore. In certain embodiments, the un-deployed position of the one or more SCU centralizers includes the one or more one or more SCU centralizers having an outer diameter that is less than an inner diameter of the production tubing, and the deployed position of the one or more one or more SCU centralizers includes the one or more one or more SCU centralizers having an outer diameter that is equal to or greater than an inner diameter of the wall of the target zone of the open-holed portion of the wellbore.

In some embodiments, at least one of the one or more anchoring seals is retrievable, and at least one of the anchoring seals that is retrievable is adapted to be removed from the target zone with a body of the SCU when the body of the SCU is removed from the target zone. In certain embodiments, at least one of the one or more anchoring seals is detachable, and at least one of the anchoring seals that is detachable is adapted to detach from a body of the SCU and remain in the target zone when the body of the SCU is removed from the target zone. In some embodiments, at least one of the anchoring seals that is detachable includes an interior passage having an internal diameter that is equal to or greater than an internal diameter of the production tubing. In certain embodiments, at least one of the one or more anchoring seals is non-retrievable, and at least one of the anchoring seals that is non-retrievable is adapted to be inflated with a hardening substance and to detach from a body of the SCU and remain in the target zone when the body of the SCU is removed from the target zone. In some embodiments, at least one of the anchoring seals that is non-retrievable includes an interior passage having an internal diameter that is equal to or greater than an internal diameter of the production tubing. In certain embodiments, the deployed position of the one or more SCU anchoring seals is adapted to isolate a region of the target zone including a breakthrough of fluid to inhibit the fluid of the breakthrough from flowing into the wellbore.

In some embodiments, the SCU includes a plurality of SCUMs assembled to one another. In certain embodiments, the plurality of SCUMs are adapted to be assembled to one another prior to the SCU being passed through the production tubing to form the SCU prior to the SCU being passed through the production tubing. In some embodiments, the plurality of SCUMs are adapted to be advanced through the production tubing unassembled, and to be assembled to one another in the open-holed portion of the wellbore to form the SCU down-hole after the SCUMs are passed through the production tubing. In certain embodiments, the SCU wireless transceiver is configured to, in response to establishing commutation with the surface control system of the well, communicate directly with the surface control system of the well. In some embodiments, the system further includes a positioning device adapted to provide a motive force to advance the SCU through the production tubing and the wellbore. In some embodiments, the system further includes the production tubing disposed in the wellbore and the surface control system of the well.

Provided in some embodiments is a thru-tubing completion system including the following: a surface control system; production tubing disposed in a wellbore of a well; and a SCU adapted to pass through the production tubing and to be disposed in a target zone of an open-holed portion of the wellbore and perform completion operations in the target zone. The SCU including a SCU wireless transceiver, one or more SCU anchoring seals adapted to be positioned in an un-deployed position and a deployed position (the un-deployed position of the one or more SCU anchoring seals enabling the SCU to pass through the production tubing disposed in the wellbore of the well, and the deployed position of the one or more SCU anchoring seals providing a seal against a wall of the target zone of the open-holed portion of the wellbore to provide zonal isolation between regions in the wellbore), and one or more SCU centralizers adapted to be positioned in an un-deployed position and a deployed position (the un-deployed position of the one or more SCU centralizers enabling the SCU to pass through the production tubing disposed in the wellbore of the well, and the deployed position of the one or more SCU centralizers positioning the SCU in the target zone of the open-holed portion of the wellbore). The system further including the following: a down-hole wireless transceiver adapted to be disposed at a down-hole end of the production tubing in the wellbore of the well, to be communicatively coupled to the surface control system of the well, to communicate wirelessly with the SCU wireless transceiver, and to provide for communication between the SCU wireless transceiver and the surface control system of the well; and a positioning device adapted to provide a motive force to advance the SCU through the production tubing and the wellbore.

Provided in some embodiments is a method of completing a target zone of a wellbore of a well, the method including the following: passing a SCU through production tubing disposed in a wellbore of a well; passing the SCU though the wellbore of the well to a target zone of an open-holed portion of the wellbore; deploying one or more SCU centralizers of the SCU to position the SCU in the target zone of the open-hole portion of the wellbore; and deploying one or more SCU anchoring seals of the SCU to seal against a wall of the target zone of the open-hole portion of the wellbore to provide zonal isolation between regions in the wellbore.

In certain embodiments, passing the SCU through the production tubing includes passing the SCU through the production tubing in an un-deployed configuration including the one or more SCU centralizers and the one or more SCU anchoring seals in an un-deployed state having an outer diameter that is less than an inner diameter of the production tubing. In some embodiments, the SCU includes a plurality of SCUMs assembled to one another, and the method further includes assembling the plurality of SCUMs to one another to form the SCU prior to the SCU being passed through the production tubing. In certain embodiments, the SCU includes a plurality SCUMs assembled to one another, and the method further includes passing the plurality of SCUMs through the production tubing unassembled to one another, and assembling the plurality of SCUMs to one another in the open-holed portion of the wellbore to form the SCU down-hole after the SCUMs are passed through the production tubing. In some embodiments, the SCU includes a SCU wireless transceiver adapted to communicate with a surface control system of the well by way of wireless communication with a down-hole wireless transceiver, and the method further includes providing the down-hole wireless transceiver at a down-hole end of the production tubing in the wellbore of the well (the down-hole wireless transceiver being communicatively coupled to a surface control system of the well, and adapted communicate wirelessly with the SCU wireless transceiver, and to provide for communication between the SCU wireless transceiver and the surface control system of the well). In certain embodiments, the method includes, in response to the SCU wireless transceiver establishing communication with the surface control system of the well, the SCU wireless transceiver communicating directly with the surface control system of the well.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idref="DRAWINGS">FIG. 1</figref> is a diagram that illustrates a well environment in accordance with one or more embodiments.

<figref idref="DRAWINGS">FIGS. 2A-4B</figref> are diagrams that illustrate sub-surface completion units (SCUs) in accordance with one or more embodiments.

<figref idref="DRAWINGS">FIGS. 5A-5C</figref> are diagrams that illustrate a detachable anchoring seal in accordance with one or more embodiments.

<figref idref="DRAWINGS">FIGS. 6A-6D</figref> are diagrams that illustrate modular SCUs in accordance with one or more embodiments.

<figref idref="DRAWINGS">FIG. 7</figref> is a flowchart that illustrates a method of operating a well using a thru-tubing completion system (TTCS) employing SCUs in accordance with one or more embodiments.

<figref idref="DRAWINGS">FIG. 8</figref> is a diagram that illustrates an example computer system in accordance with one or more embodiments.

While this disclosure is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and will be described in detail. The drawings may not be to scale. It should be understood that the drawings and the detailed descriptions are not intended to limit the disclosure to the particular form disclosed, but are intended to disclose modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the claims.

DETAILED DESCRIPTION

Described are embodiments of systems and methods of operating a well using a thru-tubing completion system (TTCS) employing subsurface completion units (SCUs). In some embodiments, a TTCS includes one or more SCUs that are deployed down-hole, in a wellbore having a production tubing string in place. For example, a SCU may be delivered through the production tubing to a target zone of the wellbore in need of completion, such as an open-holed portion of the wellbore that is down-hole from a down-hole end of the production tubing and that is experiencing breakthrough. In some embodiments, a deployed SCU is operated to provide completion of an associated target zone of the wellbore. For example, seals and valves of a deployed SCU may be operated to provide providing zonal fluid isolation of annular regions of the wellbore located around the SCU, to control the flow of breakthrough fluids into a stream of production fluids flowing up the wellbore and the production tubing.

In some embodiments, a SCU includes a modular SCU formed of one or more SCU modules (SCUMs). For example, multiple SCUMs may be stacked in series, end-to-end, to form a relatively long SCU that can provide completion of a relatively long section of a wellbore. This can provide additional flexibility as a suitable numbers of SCUMs may be stacked together to provide a desired length of completion in a wellbore. In some embodiments, the SCUMs can be assembled at the surface or down-hole. This can further enhance the flexibility of the system by reducing the number of down-hole runs needed to install the SCUs, by providing flexibility in the physical size of the SCU to be run through the production tubing and the wellbore, and by providing flexibility to add or remove SCUMs at a later time, as the well evolves over time. The ability to run the SCUs through the production tubing can enable the SCUs to provide completion functions, such as lining a wellbore of a well to inhibit breakthrough, without having to remove and re-run the production tubing in the well during installation or retrieval of the SCUs.

<figref idref="DRAWINGS">FIG. 1</figref> is a diagram that illustrates a well environment <b>100</b> in accordance with one or more embodiments. In the illustrated embodiment, the well environment <b>100</b> includes a hydrocarbon reservoir (or “reservoir”) <b>102</b> located in a subsurface formation (a “formation”) <b>104</b>, and a hydrocarbon well system (or “well system”) <b>106</b>.

The formation <b>104</b> may include a porous or fractured rock formation that resides underground, beneath the earth's surface (or “surface”) <b>107</b>. In the case of the well system <b>106</b> being a hydrocarbon well, the reservoir <b>102</b> may include a portion of the formation <b>104</b> that contains (or that is determined to or expected to contain) a subsurface pool of hydrocarbons, such as oil and gas. The formation <b>104</b> and the reservoir <b>102</b> may each include different layers of rock having varying characteristics, such as varying degrees of permeability, porosity, and resistivity. In the case of the well system <b>106</b> being operated as a production well, the well system <b>106</b> may facilitate the extraction of hydrocarbons (or “production”) from the reservoir <b>102</b>. In the case of the well system <b>106</b> being operated as an injection well, the well system <b>106</b> may facilitate the injection of fluids, such as water, into the reservoir <b>102</b>. In the case of the well <b>106</b> being operated as a monitoring well, the well system <b>106</b> may facilitate the monitoring of characteristics of the reservoir <b>102</b>, such reservoir pressure or water encroachment.

The well system <b>106</b> may include a hydrocarbon well (or “well”) <b>108</b> and a surface system <b>109</b>. The surface system <b>109</b> may include components for developing and operating the well <b>108</b>, such as a surface control system <b>109</b><i>a</i>, a drilling rig, a production tree, and a workover rig. The surface control system <b>109</b><i>a </i>may provide for controlling and monitoring various well operations, such as well drilling operations, well completion operations, well production operations, and well and formation monitoring operations. In some embodiments, the surface control system <b>109</b><i>a </i>may control surface operations and down-hole operations. These operations may include operations of a subsurface positioning device <b>123</b> and SCUs <b>122</b> described here. For example, the surface control system <b>109</b><i>a </i>may issue commands to the subsurface positioning device <b>123</b> or the SCUs <b>122</b> to control operation of the respective devices, including the various operations described here. In some embodiments, the surface control system <b>109</b><i>a </i>includes a computer system that is the same as or similar to that of computer system <b>1000</b> described with regard to at least <figref idref="DRAWINGS">FIG. 8</figref>.

The well <b>108</b> may include a wellbore <b>110</b> that extends from the surface <b>107</b> into the formation <b>104</b> and the reservoir <b>102</b>. The wellbore <b>110</b> may include, for example, a mother-bore <b>112</b> and one or more lateral bores <b>114</b> (for example, lateral bores <b>114</b><i>a </i>and <b>114</b><i>b</i>). The well <b>108</b> may include completion elements, such as casing <b>116</b> and production tubing <b>118</b>. The casing <b>116</b> may include, for example, tubular sections of steel pipe lining an inside diameter of the wellbore <b>110</b> to provide structural integrity to the wellbore <b>110</b>. The casing <b>116</b> may include filling material, such as cement, disposed between the outside surface of the steel pipe and the walls of the wellbore <b>110</b>, to further enhance the structural integrity of the wellbore <b>110</b>. The portions of the wellbore <b>110</b> having casing <b>116</b> installed may be referred to as a “cased” portions of the wellbore <b>110</b>; the portions of the wellbore <b>110</b> not having casing <b>116</b> installed may be referred to as a “open-holed” or “un-cased” portions of the wellbore <b>110</b>. For example, the upper portion of the illustrated wellbore <b>110</b> having casing <b>116</b> installed may be referred to as the cased portion of the wellbore <b>110</b>, and the lower portion of the wellbore <b>110</b> below (or “down-hole” from) the lower end of the casing <b>116</b> may be referred to as the un-cased (or open-holed) portion of the wellbore <b>110</b>.

The production tubing <b>118</b> may include a tubular pipe that extends from the surface system <b>109</b> into the wellbore <b>110</b> and that provides a conduit for the flow of production fluids between the wellbore <b>110</b> and the surface <b>107</b>. For example, production fluids in the wellbore <b>110</b> may enter the production tubing <b>118</b> at a down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b>, the production fluids may travel up a central passage in the production tubing <b>118</b> to a production tree coupled to an up-hole end <b>118</b><i>b </i>of the production tubing <b>118</b> at the surface <b>107</b>, and the production tree may route the production fluids a production collection and distribution network. The production tubing <b>118</b> may be disposed in one or both of cased and uncased portions of the wellbore <b>110</b>. The production tubing <b>118</b> may have an inner diameter (ID) that is of sufficient size to facilitate the flow of production fluids through the production tubing <b>118</b>. The production tubing <b>118</b> may have an outer diameter (OD) that is less than an ID of the components it passes through, such as the casing <b>116</b> or open-holed portions of the wellbore <b>110</b>, to facilitate its installation in the wellbore <b>110</b>. For example, the open-holed portion of the wellbore <b>110</b> may have an ID of about 6 inches (about 15 centimeters (cm)) and the production tubing <b>118</b> may have an OD of about 5 inches (about 13 cm) and an ID of about 4 inches (about 10 cm). In some embodiments, a portion of the wellbore <b>110</b> below the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b> is open-holed. For example, in the illustrated embodiment, the portion of the wellbore <b>110</b> down-hole of the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b> includes an open-holed, horizontally oriented portion of the mother-bore <b>112</b> and the open-holed lateral-bores <b>114</b><i>a </i>and <b>114</b><i>b. </i>

In some embodiments, the well system <b>106</b> includes a thru-tubing completion system (TTCS) <b>120</b>. The TTCS <b>120</b> may include one or more sub-surface completion units (SCUs) <b>122</b> Each of the sub-surface completion units <b>122</b> may be disposed in, and provide for completion of, a respective target zone <b>124</b> of the wellbore <b>110</b>. For example, a first SCU <b>122</b><i>a </i>may be disposed in a first target zone <b>124</b><i>a </i>in the wellbore <b>110</b> to control an undesirable breakthrough of water at the first target zone <b>124</b><i>a</i>, a second SCU <b>122</b><i>b </i>may be disposed in a second target zone <b>124</b><i>b </i>in the wellbore <b>110</b> to control an undesirable breakthrough of gas at the second target zone <b>124</b><i>b</i>, and a third SCU <b>122</b><i>c </i>may be disposed at a third target zone <b>124</b><i>c </i>in the wellbore <b>110</b> to seal off the lateral <b>114</b><i>b </i>to control an undesirable breakthrough of water in the distal (or “down-hole”) portion of the lateral <b>114</b><i>b </i>located down-hole of the target zone <b>124</b><i>c</i>. In some embodiments, the first, second or third SCU <b>122</b><i>a</i>, <b>122</b><i>b </i>or <b>122</b><i>c </i>may be the same or similar to SCUs described here, such as SCUs <b>122</b>, <b>122</b>′, <b>122</b>″, <b>122</b>′″ and modular SCUs <b>170</b>, <b>170</b>′, <b>170</b>″ and <b>170</b>′″.

In some embodiments, a SCU <b>122</b> is advanced to a target zone <b>124</b> by way of the production tubing <b>118</b>. For example, referring to SCU <b>122</b><i>a</i>, the SCU <b>122</b><i>a </i>may be advanced through an internal passage of the production tubing <b>118</b> such that it exits the production tubing <b>118</b> and enters the open-holed portion of the wellbore <b>110</b> at the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b>, and then be advanced through the open-holed portion of the wellbore <b>110</b> to the target zone <b>124</b><i>a. </i>

In some embodiments, a SCU <b>122</b> is advanced through the production tubing <b>118</b> in an un-deployed configuration. In an un-deployed configuration, one or more expandable elements of the SCU <b>122</b>, such as centralizers and anchoring seals, are provided in a retracted (or “un-deployed”) position. In an un-deployed configuration the overall size of the SCU <b>122</b> may be relatively small in comparison to an overall size of the SCU <b>122</b> in a deployed configuration (which may include the one or more expandable elements of the SCU <b>122</b> provided in an extended (or “deployed”) position). The un-deployed configuration may enable the SCU <b>122</b> to pass through the internal passage of the production tubing <b>118</b>, and a smallest cross-section of an intervening portion of the wellbore <b>110</b> between the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b> and the target zone <b>124</b>. For example, where the production tubing <b>118</b> has an ID of about 4 inches (about 10 cm) and the intervening open-holed portion of the wellbore <b>110</b> between the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b> and the target zone <b>124</b><i>a </i>has a minimum cross-sectional diameter of about 5 inches (about 13 cm), the SCU <b>122</b><i>a </i>may have an OD of about 4 inches (about 10 cm) or less in its un-deployed configuration. This may enable the SCU <b>122</b><i>a </i>to pass freely from the surface <b>107</b> to the target zone <b>124</b><i>a </i>by way of the production tubing <b>118</b> and the intervening portion of the wellbore <b>110</b>. As a further example, where the production tubing has an ID of about 4 inches (about 10 cm) and the intervening open-holed portion of the wellbore <b>110</b> between the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b> and the target zone <b>124</b><i>b </i>has a minimum cross-sectional diameter of about 3 inches (about 7.5 cm), the SCU <b>122</b><i>b </i>may have an OD of 3 inches (about 7.5 cm) or less in its un-deployed configuration. This may to enable the SCU <b>122</b><i>b </i>to pass freely from the surface <b>107</b> to the target zone <b>124</b><i>b </i>by way of the production tubing <b>118</b> and the intervening portion of the wellbore <b>110</b>.

In a deployed configuration of a SCU <b>122</b>, one or more expandable elements of the SCU <b>122</b>, such as centralizers and anchoring seals, are provided in an extended (or “deployed”) position to facilitate to provide completion operations, such as the SCU <b>122</b> sealing off at least a portion of a target zone <b>124</b>. For example, a SCU <b>122</b> may have positioning devices, such as centralizers that are expanded radially outwardly into a deployed configuration to center the SCU <b>122</b> in the wellbore <b>110</b>, and anchoring seals that are expanded radially outwardly to engage and seal against a wall of the wellbore <b>110</b> located about the SCU <b>122</b>. A centralizer may include a member, such as an arm or hoop, that is extended radially to engage the wall of the wellbore <b>110</b> and bias a body of the SCU <b>122</b> away from the wall of the wellbore <b>110</b>. This biasing may “center” the body of the SCU <b>122</b> in the wellbore <b>110</b>. An anchoring seal may include a sealing member, such as a ring shaped inflatable bag disposed about the exterior of a body of a SCU <b>122</b>, that is expanded radially to provide a fluid seal between an exterior of a body of the SCU <b>122</b> and the wall of the wellbore <b>110</b>. This may provide fluid seal between regions on opposite sides of the sealing member, and in effect provide “zonal fluid isolation” between regions on opposite sides of the sealing member. In a deployment operation for a SCU <b>122</b>, centralizers of the SCU <b>122</b> may be extended first, to bias a body of the SCU <b>122</b> away from the walls of the wellbore <b>110</b> and center the SCU <b>122</b>, and anchoring seals of the SCU <b>122</b> may be expanded second to secure the SCU <b>122</b> within the wellbore <b>110</b> and to provide zonal fluid isolation of regions in the wellbore located on opposite sides of each of the anchoring seals.

In a deployed configuration, a lateral cross-sectional size of the SCU <b>122</b> (for example, an OD of the SCU <b>122</b>) may be relatively large in comparison to a lateral cross-sectional size of the SCU <b>122</b> in an un-deployed configuration. An OD of the SCU <b>122</b> may be equal to or greater than cross-sectional size (for example, ID) of the target zone <b>124</b> of the wellbore <b>110</b>. For example, the centralizers of the SCU <b>122</b> may have a fully expanded size that is greater than the size of the target zone <b>124</b> of the wellbore <b>110</b> in its deployed state to provide a biasing force to move a body of the SCU <b>122</b> away from the walls of the wellbore <b>110</b>. As a further example, the anchoring seals of the SCU <b>122</b> may have a fully expanded size that is greater than the size of the target zone <b>124</b> of the wellbore <b>110</b> in its deployed state to provide sealing contact at the interface of the anchoring seal <b>128</b> and the wall of the wellbore <b>110</b>. In some embodiments, a SCU <b>122</b> is maintained in an un-deployed configuration in which the SCU <b>122</b> has a relatively small size, while the SCU <b>122</b> is advanced from the surface <b>107</b> to a target zone <b>124</b> by way of the production tubing <b>118</b> and an intervening portion of the wellbore <b>110</b> between the down-hole end <b>118</b><i>a </i>of the production tubing and the target zone <b>124</b>. Once the SCU <b>122</b> is positioned in the target zone <b>124</b>, the SCU <b>122</b> may be deployed, including expanding its centralizers and anchoring seals, to provide completion operations, such as zonal fluid isolation of at least a portion of the target zone <b>124</b>. Thus, a SCU <b>122</b> may have the flexibility to be passed through a relatively small production tubing <b>118</b> in a wellbore <b>110</b>, and still provide completions operations in a portion of the wellbore <b>110</b> having a relatively large cross-sectional area.

In some embodiments, a SCU <b>122</b> is retrievable. For example, the SCU <b>122</b><i>a </i>may be delivered to and deployed in a target zone <b>124</b><i>a</i>, and later be retrieved from the target zone <b>124</b><i>a </i>when the SCU <b>122</b><i>a </i>is no longer needed in the target zone <b>124</b><i>a </i>or to provide for passage of other devices through the target zone <b>124</b><i>a</i>. In some embodiments, a retrievable SCU <b>122</b> can be repositioned within the wellbore <b>110</b>. For example, the SCU <b>122</b><i>a </i>may be deployed in the target zone <b>124</b><i>a </i>to address a breakthrough at the target zone <b>124</b><i>a</i>, and after the breakthrough in the target zone <b>124</b><i>a </i>is resolved and a new breakthrough has occurred in the target zone <b>124</b><i>c</i>, the SCU <b>122</b><i>a </i>may be moved from the target zone <b>124</b><i>a </i>to the target zone <b>124</b><i>c </i>to address the breakthrough at target zone <b>124</b><i>c. </i>

In some embodiments, a SCU <b>122</b> communicates wirelessly with other components of the system, including the surface system <b>109</b>. For example, the SCU <b>122</b> may include a SCU wireless transceiver that can communicate wirelessly with a down-hole wireless transceiver <b>125</b>. The down-hole wireless transceiver <b>125</b> may function as an intermediary for relaying communications between the surface control system <b>109</b><i>a </i>and the SCU <b>122</b>. The down-hole wireless transceiver <b>125</b> may be disposed, for example, at or near the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b>. For example, the down-hole wireless transceiver <b>125</b> may be located within about 20 feet (about 6 meters) of the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b>. The down-hole wireless transceiver <b>125</b> may be communicatively coupled to the surface control system <b>109</b><i>a</i>. For example, the wireless transceiver <b>125</b> may have a wired or wireless connection to the surface control system <b>109</b><i>a</i>. As a result, in some embodiments, the SCU <b>122</b> can be deployed in the wellbore <b>110</b>, physically untethered from the production tubing <b>118</b> and the surface system <b>109</b>, and the SCU <b>122</b> can operate as a standalone unit that communicates wirelessly with the surface control system <b>109</b><i>a </i>by way of the down-hole wireless transceiver <b>125</b>.

In some embodiments, positioning of a SCU <b>122</b> is facilitated by a subsurface positioning device <b>123</b>, such as a tractor. The subsurface positioning device <b>123</b> may be capable of navigating the interior passage of the production tubing <b>118</b> and the interior of the wellbore <b>110</b>, and be capable of providing the motive force (for example, pushing or pulling) necessary to advance the SCU <b>122</b> through the production tubing <b>118</b> and the wellbore <b>110</b>. For example, during an installation operation, the positioning device <b>123</b> may couple to a trailing end (or “up-hole”) end of the SCU <b>122</b><i>a </i>while located at the surface <b>107</b>, and push the SCU <b>122</b><i>a </i>down-hole, through the production tubing <b>118</b> and along the intervening open-holed portion of the wellbore <b>110</b>, into position at the target zone <b>124</b><i>a</i>. During a retrieval operation, the positioning device <b>123</b> may couple to the up-hole end of the SCU <b>122</b><i>a </i>while it is positioned in the target zone <b>124</b><i>a</i>, and pull the SCU <b>122</b><i>a </i>up-hole from the target zone <b>124</b><i>a</i>, along the intervening open-holed portion of the wellbore <b>110</b> and through the production tubing <b>118</b>, to the surface <b>107</b>. During a repositioning operation, the positioning device <b>123</b> may couple to the up-hole end of the SCU <b>122</b><i>a </i>while it is located in the target zone <b>124</b><i>a</i>, pull the SCU <b>122</b><i>a </i>up-hole from the target zone <b>124</b><i>a</i>, along the open-holed portion of the wellbore <b>110</b>, and push the SCU <b>122</b><i>a </i>to another target zone <b>124</b>, such as the target zone <b>124</b><i>c. </i>

In some embodiments, the subsurface positioning device <b>123</b> may not be rigidly coupled to the surface system <b>109</b>. For example, the subsurface positioning device <b>123</b> may include a down-hole tractor having a local propulsion system that provides the motive force necessary to propel the subsurface positioning device <b>123</b> and SCUs <b>122</b> through the production tubing <b>118</b> and the wellbore <b>110</b>. The local propulsion system may include, for example, an onboard battery, an electrical motor driven by the battery, and wheels or tracks driven by the motor. In some embodiments, the subsurface positioning device <b>123</b> is tethered to the surface system <b>109</b>. For example, the subsurface positioning device <b>123</b> may have a wired connection to the surface system <b>109</b> that provides for data communication between the positioning device <b>123</b> and the surface system <b>109</b>, and the transfer of electrical power from the surface system <b>109</b> to the positioning device <b>123</b>. In some embodiments, the subsurface positioning device <b>123</b> is not directly tethered to the surface system <b>109</b>. For example, the subsurface positioning device <b>123</b> may have a wireless transceiver <b>123</b><i>a </i>that provides wireless communication with the surface system <b>109</b> or the down-hole wireless transceiver <b>125</b>. In such an embodiment, the subsurface positioning device <b>123</b> may communicate wirelessly with the surface system <b>109</b> directly or by way of wireless communication between wireless transceiver <b>123</b><i>a </i>and the down-hole wireless transceiver <b>125</b>. For example, in response to determining that wireless communication can be established directly between the wireless transceiver <b>123</b><i>a </i>and the surface system <b>109</b> (for example, the SCU <b>122</b> has sufficient power available and the surface system <b>109</b> is within communication range of the wireless transceiver <b>123</b><i>a</i>), the wireless transceiver <b>123</b><i>a </i>may communicate directly with the surface system <b>109</b> by way of wireless communication. In response to determining that wireless communication cannot be established directly between the wireless transceiver <b>123</b><i>a </i>and the surface system <b>109</b> (for example, the SCU <b>122</b> does not have sufficient power available or the surface system <b>109</b> is not within communication range of the wireless transceiver <b>123</b><i>a</i>), the wireless transceiver <b>123</b><i>a </i>may communicate indirectly with the surface system <b>109</b>, by way of the down-hole wireless transceiver <b>125</b> (for example, the down-hole wireless transceiver <b>125</b> may relay communications between the wireless transceiver <b>123</b><i>a </i>and the surface system <b>109</b>). In some embodiments, the wireless transceiver <b>123</b><i>a </i>may communicate indirectly with the surface system <b>109</b>, by way of the down-hole wireless transceiver <b>125</b>, regardless of whether wireless communication can be established directly between the wireless transceiver <b>123</b><i>a </i>and the surface system <b>109</b>. The communication between the positioning device <b>123</b> and the surface system <b>109</b> may include, for example, commands from the surface system <b>109</b> to control operation of the positioning device <b>123</b>, or reporting data from the positioning device <b>123</b>, such as providing feedback on the status and operation of the positioning device <b>123</b> or down-hole environmental conditions.

In some embodiments, the subsurface positioning device <b>123</b> may communicate wirelessly with the SCUs <b>122</b>. For example, in an instance in which wireless communications from the SCU <b>122</b><i>a </i>located in the target zone <b>124</b><i>a </i>is not able to reach the down-hole wireless transceiver <b>125</b>, the positioning device <b>123</b> may be moved into a location between the down-hole wireless transceiver <b>125</b> and the target zone <b>124</b><i>a</i>, and the wireless positioning device <b>123</b> may relay communications between the down-hole wireless transceiver <b>125</b> and a wireless transceiver of the SCU <b>122</b><i>a </i>by way of the wireless transceiver <b>123</b><i>a</i>. In some embodiments, the subsurface positioning device <b>123</b> may include an inductive coupler <b>123</b><i>b </i>that enables the positioning device <b>123</b> to communicate with a complementary inductive coupler of a SCU <b>122</b>. For example, if the down-hole end of the positioning device <b>123</b> includes a first inductive coupler <b>123</b><i>a</i>, the up-hole end of the SCU <b>122</b><i>a </i>includes a second inductive coupler, and the down-hole end of the positioning device <b>123</b> is coupled to the up-hole end of the SCU <b>122</b><i>a</i>, such that the first and second inductive couplers are inductively coupled and capable of transmitting communications, the positioning device <b>123</b> and the SCU <b>122</b><i>a </i>may communicate with one another by way of the first and second inductive couplers.

<figref idref="DRAWINGS">FIGS. 2A-4B</figref> are diagrams that illustrate longitudinally cross-sectioned views of example SCUs <b>122</b>, including SCUs <b>122</b>′, <b>122</b>″ and <b>122</b>′″, in accordance with one or more embodiments. <figref idref="DRAWINGS">FIGS. 2A, 3A and 4A</figref> illustrate the example SCUs <b>122</b> in deployed configurations, and <figref idref="DRAWINGS">FIGS. 2B, 3B and 4B</figref> illustrate the example SCUs <b>122</b> in un-deployed configurations in accordance with one or more embodiments.

In some embodiments, a SCU <b>122</b> includes one or more positioning devices that provide positioning of the SCU <b>122</b> in the wellbore <b>110</b> or zonal fluid isolation of regions within of the wellbore <b>110</b>. The positioning devices may include one or more centralizers <b>126</b> and one or more anchoring seals <b>128</b>. A centralizer <b>126</b> of a SCU <b>122</b> may be deployed to bias a body of the SCU <b>122</b> away from the walls of the wellbore <b>110</b>. This biasing may effectively “center” the SCU <b>122</b> within the wellbore <b>110</b>. An anchoring seal <b>128</b> of a SCU <b>122</b> may be deployed to secure (or “anchor”) the SCU <b>122</b> within the wellbore <b>110</b> and to provide a fluid seal between adjacent regions of the wellbore <b>110</b>, referred to as zonal fluid isolation of the adjacent regions.

In some embodiments, a SCU <b>122</b> includes a body <b>130</b>. The SCU <b>122</b> and the body <b>130</b> of the SCU <b>122</b> may be defined as having a first (“leading” or “down-hole”) end <b>132</b> and a second (“trailing” or “up-hole”) end <b>134</b>. The down-hole end <b>132</b> of the SCU <b>122</b> and the body <b>130</b> may refer to an end of the SCU <b>122</b> and the body <b>130</b> to be advanced first into the wellbore <b>110</b>, ahead of the opposite, up-hole end <b>134</b> of the SCU <b>122</b> and the body <b>130</b>. When positioned in the wellbore <b>110</b>, the down-hole end <b>132</b> of the SCU <b>122</b> and the body <b>130</b> may refer to an end of the SCU <b>122</b> and the SCU body <b>130</b> that is nearest to the down-hole end of the wellbore <b>110</b>, and the up-hole end <b>134</b> of the SCU <b>122</b> and the body <b>130</b> may refer to an end of the SCU <b>122</b> and the SCU body <b>130</b> that is nearest to the surface <b>107</b> by way of the wellbore <b>110</b>. In some embodiments, the body <b>130</b> includes a tubular member that defines a central passage <b>136</b>. The central passage <b>136</b> may act as a conduit to direct fluid flow through the SCU <b>122</b>, between a portion of the wellbore <b>110</b> located down-hole of the SCU <b>122</b> and a portion of the wellbore <b>110</b> located up-hole of the SCU <b>122</b>. Referring to the SCU <b>122</b>′ of <figref idref="DRAWINGS">FIGS. 2A and 2B</figref>, the SCU <b>122</b>″ of <figref idref="DRAWINGS">FIGS. 3A and 3B</figref> and the SCU <b>122</b>′ of <figref idref="DRAWINGS">FIGS. 4A and 4B</figref>, each of the SCUs <b>122</b>′, <b>122</b>″ and <b>122</b>′ and the respective SCU bodies <b>130</b> include a down-hole end <b>132</b> and an up-hole end <b>134</b>.

In some embodiments, a centralizer <b>126</b> of a SCU <b>122</b> includes one or more members that are extended radially outward, from a retracted (or “un-deployed”) position to an expanded (or “deployed”) position, to engage (for example, press against) the wall of the wellbore <b>110</b> and bias the body <b>130</b> of the SCU <b>122</b> away from the wall of the wellbore <b>110</b>. This may “center” the body <b>130</b> of the SCU <b>122</b> in the wellbore <b>110</b>. Centering of the body <b>130</b> may involve creating an annular region around the body <b>130</b>, between the walls of the wellbore <b>110</b> and an exterior of the body <b>130</b>. A centralizer <b>126</b> may be a flexible arm or hoop that is held in a retracted (un-deployed) position while the SCU <b>122</b> is moved through the production tubing <b>118</b> and the wellbore <b>110</b> into a target zone <b>124</b> of the wellbore <b>110</b>, and that is expanded (deployed) while the SCU <b>122</b> is located in the target zone <b>124</b>, to bias the body <b>130</b> of the SCU <b>122</b> away from the wall of the wellbore <b>110</b>.

Referring to the example SCU <b>122</b>′ of <figref idref="DRAWINGS">FIGS. 2A and 2B</figref>, each of the centralizers <b>126</b> of the SCU <b>122</b>′ may include a respective set of arms disposed about an exterior of the body <b>130</b> of the SCU <b>122</b>′, at a respective longitudinal position along a length of the body <b>130</b> of the SCU <b>122</b>′. Each of the centralizers <b>126</b> may, for example, be rotated from a retracted (un-deployed) position to an expanded (deployed) position to press against laterally adjacent portions of the wall of the wellbore <b>110</b> surrounding the body <b>130</b> of the SCU <b>122</b>′. Referring to the example SCU <b>122</b>″ of <figref idref="DRAWINGS">FIGS. 3A and 3B</figref>, each of the centralizers <b>126</b> of the SCU <b>122</b>″ may include a respective set of elongated members disposed about an exterior of the body <b>130</b> of the SCU <b>122</b>″, at a respective longitudinal position along a length of the body <b>130</b> of the SCU <b>122</b>″. A first (or “down-hole”) centralizer <b>126</b><i>a </i>may be located between anchoring seals <b>128</b> and the down-hole end <b>132</b> of the body <b>130</b>, and a second (or “up-hole”) centralizer <b>126</b><i>b </i>may be disposed between the anchoring seals <b>128</b> and the up-hole end <b>134</b> of the SCU body <b>130</b>. Each of the centralizers <b>126</b> may include a set of hoop shaped members that extended from a retracted (un-deployed) position (in which the members are relatively flat) to an expanded (deployed) position (in which the members form a relatively curved, crescent shape) to press against laterally adjacent portions of the wall of the wellbore <b>110</b> surrounding the body <b>130</b> of the SCU <b>122</b>″. Referring to the example SCU <b>122</b>′″ of <figref idref="DRAWINGS">FIGS. 4A and 4B</figref>, each of the centralizers <b>126</b> of the SCU <b>122</b>′″ may include a respective set of elongated members disposed about an exterior of the body <b>130</b> of the SCU <b>122</b>′″, at a respective longitudinal position along a length of the body <b>130</b> of the SCU <b>122</b>″′. Each of the centralizers <b>126</b> may, for example, be rotated from a retracted (un-deployed) position to an expanded (deployed) position to press against laterally adjacent portions of the wall of the wellbore <b>110</b> surrounding the body <b>130</b> of the SCU <b>122</b>″′.

In some embodiments, an anchoring seal <b>128</b> of a SCU <b>122</b> includes one or more sealing elements that are expanded radially outward, from a retracted (or “un-deployed”) position to an expanded (or “deployed”) position, to secure (or “anchor”) the SCU <b>122</b> within the wellbore <b>110</b> and to seal-off adjacent regions of the wellbore <b>110</b>. In some embodiments, an anchoring seal <b>128</b> is a ring shaped-element that extends laterally around the circumference of a body <b>130</b> of the SCU <b>122</b>, and is expanded radially (deployed) to engage the portion of the wall of the wellbore <b>110</b> laterally adjacent the SCU body <b>132</b>, and to form a fluid seal between the exterior of the SCU body <b>132</b> and the laterally adjacent portion of the wellbore <b>110</b>. This may provide a fluid barrier or seal between regions on opposite sides of the anchoring seal <b>128</b>, and in effect provide “zonal fluid isolation” between regions on opposite sides of the anchoring seal <b>128</b>. For example, an anchoring seal <b>128</b> of a SCU <b>122</b> may be an inflatable ring (for example, a donut shaped bladder) positioned around a circumference of the SCU body <b>130</b>. The anchoring seal <b>128</b> may remain in an uninflated (un-deployed) position while the SCU <b>122</b> is advanced to a target zone <b>124</b> of the wellbore <b>110</b> by way of the production tubing <b>118</b> and an intervening portion of the wellbore <b>110</b>. The anchoring seal <b>128</b> may be inflated (deployed) to fill an annular region between the body <b>130</b> of the SCU <b>122</b> and the walls of the wellbore <b>110</b>. The inflated anchoring seal <b>128</b> may engage (for example, seal against) the walls of the wellbore <b>110</b> in the target zone <b>124</b> to anchor the SCU <b>122</b> in the target zone <b>124</b>, and to provide a fluid seal between an exterior of the body <b>130</b> and the walls of the wellbore <b>110</b>. The resulting fluid seal may provide zonal fluid isolation between a region of the wellbore <b>110</b> down-hole of the anchoring seal <b>128</b> and a region of the wellbore <b>110</b> up-hole of the anchoring seal <b>128</b>.

Referring to the example SCU <b>122</b>′ of <figref idref="DRAWINGS">FIGS. 2A and 2B</figref>, each of the anchoring seals <b>128</b> of the SCU <b>122</b>′ may include an inflatable ring that is disposed around the exterior of the body <b>130</b> of the SCU <b>122</b>′. Each of the anchoring seals <b>128</b> may be inflated from an uninflated (un-deployed) state to an inflated (deployed) state, to secure the SCU <b>122</b>′ in the target zone <b>124</b> and create a fluid seal between the SCU body <b>130</b> of the SCU <b>122</b>′ and the walls of the wellbore <b>110</b>. The fluid seal may provide zonal fluid isolation between a region of the wellbore <b>110</b> down-hole of the anchoring seal <b>128</b> and a region of the wellbore <b>110</b> up-hole of the anchoring seal <b>128</b>. For example, a first deployed anchoring seal <b>128</b><i>a </i>of the SCU <b>122</b>′ may provide zonal fluid isolation between a first region <b>110</b><i>a </i>and a second region <b>110</b><i>b </i>of the wellbore <b>110</b>, a second deployed anchoring seal <b>128</b><i>b </i>of the SCU <b>122</b>′ may provide zonal fluid isolation between the second region <b>110</b><i>b </i>and a third region <b>110</b><i>c </i>of the wellbore <b>110</b>, and a third anchoring seal <b>128</b><i>c </i>of the SCU <b>122</b>′ may provide zonal fluid isolation between the third region <b>110</b><i>c </i>and a fourth region <b>110</b><i>d </i>of the wellbore <b>110</b>.

Referring to the example SCU <b>122</b>″ of <figref idref="DRAWINGS">FIGS. 3A and 3B</figref>, each of the anchoring seals <b>128</b> of the SCU <b>122</b>″ may include an inflatable ring that is disposed around the exterior of the body <b>130</b> of the SCU <b>122</b>″. Each of the anchoring seals <b>128</b> may be inflated from an uninflated (un-deployed) state to an inflated (deployed) state, to secure the SCU <b>122</b>′ in the target zone <b>124</b> and create a fluid seal between the SCU body <b>130</b> of the SCU <b>122</b>′ and the walls of the wellbore <b>110</b>. The fluid seal may provide zonal fluid isolation between a region of the wellbore <b>110</b> down-hole of the anchoring seal <b>128</b> and a region of the wellbore <b>110</b> up-hole of the anchoring seal <b>128</b>. For example, a first deployed anchoring seal <b>128</b><i>d </i>of the SCU <b>122</b>″ may provide zonal fluid isolation between a first region <b>110</b><i>e </i>and a second region <b>110</b><i>f </i>of the wellbore <b>110</b>, and a second anchoring seal <b>128</b><i>e </i>of the SCU <b>122</b>″ may provide zonal fluid isolation between the second region <b>110</b><i>f </i>and a third region <b>110</b><i>g </i>of the wellbore <b>110</b>.

Referring to the example SCU <b>122</b>′″ of <figref idref="DRAWINGS">FIGS. 4A and 4B</figref>, the anchoring seal <b>128</b> of the SCU <b>122</b>′″ may include an inflatable ring that is disposed around the exterior of the body <b>130</b> of the SCU <b>122</b>′″. The anchoring seal <b>128</b> may be inflated from an uninflated (un-deployed) state to an inflated (deployed) state, to secure the SCU <b>122</b>′″ in the target zone <b>124</b> and create a fluid seal between the SCU body <b>130</b> of the SCU <b>122</b>′″ and the walls of the wellbore <b>110</b>. The fluid seal may provide zonal fluid isolation between a region of the wellbore <b>110</b> down-hole of the anchoring seal <b>128</b> and a region of the wellbore <b>110</b> up-hole of the anchoring seal <b>128</b>. For example, the deployed anchoring seal <b>128</b> of the SCU <b>122</b>′″ may provide zonal fluid isolation between a first region <b>110</b><i>h </i>and a second region <b>110</b><i>i </i>of the wellbore <b>110</b>.

The size of a SCU <b>122</b> may be defined by the extents of a lateral cross-sectional profile of the SCU <b>122</b>. A deployed size of a SCU <b>122</b> may be defined, for example, by the extents of the lateral cross-sectional profile of the SCU <b>122</b> with the centralizers <b>126</b> and anchoring seals <b>128</b> of the SCU <b>122</b> in an extended (deployed) position. An un-deployed size of a SCU <b>122</b> may be defined, for example, by the extents of the lateral cross-sectional profile of the SCU <b>122</b> with the centralizers <b>126</b> and the anchoring seals <b>128</b> of the SCU <b>122</b> in a retracted (un-deployed) position. The un-deployed size <b>137</b> of a SCU <b>122</b>, for example, be a maximum diameter of the lateral cross-sectional profile of the SCU <b>122</b> with the centralizers <b>126</b> and anchoring seals <b>128</b> of the SCU <b>122</b> in a retracted (un-deployed) position. The un-deployed size <b>137</b> of a SCU <b>122</b> may be, for example, less than the smallest lateral cross-sectional profile of the path that it travels along from the surface <b>107</b> to the target zone <b>124</b>, such as the smallest of the ID of the production tubing <b>118</b> and the ID of the intervening portion of the wellbore <b>110</b> between the surface <b>107</b> and the target zone <b>124</b>. <figref idref="DRAWINGS">FIGS. 2B, 3B and 4B</figref> illustrate the SCUs <b>122</b>′, <b>122</b>″ and <b>122</b>′″ in un-deployed configurations, and their respective un-deployed sizes <b>137</b>. The un-deployed size <b>137</b> of each of the SCUs <b>122</b>′, <b>122</b>″ and <b>122</b>′″ may be defined by the extents of its lateral cross-sectional profile (for example, a minimum diameter that encompasses the entire lateral cross-sectional profile of the SCU).

In some embodiments, an anchoring seal <b>128</b> is detachable. A detachable anchoring seal <b>128</b> may be designed to detach (or “decouple”) from a body <b>130</b> of a SCU <b>122</b>. This may enable the SCU <b>122</b> to deploy the anchoring seal <b>128</b> in a target zone <b>124</b>, to detach from the anchoring seal <b>128</b>, and to move from the target zone <b>124</b>, leaving the anchoring seal <b>128</b> deployed in the wellbore <b>110</b>. This may be advantageous, for example, in the instance a region of the wellbore <b>110</b> down-hole of the target zone <b>124</b> needs to be accessed. In such an instance, the SCU <b>122</b> can be removed (without having to un-deploy the anchoring seal <b>128</b>), the region of the wellbore <b>110</b> down-hole of the target zone <b>124</b> can be accessed through a central passage in the anchoring seal <b>128</b> that remains deployed in the target zone <b>124</b>, and once access is no longer needed, the SCU <b>122</b> can be returned into position in the target zone <b>124</b> and re-attached (“re-coupled”) to the anchoring seal <b>128</b> still deployed in the target zone <b>124</b>. In some embodiments, the coupling between a detachable anchoring seal <b>128</b> and a body <b>130</b> of a SCU <b>122</b> is facilitated by a radially expanding member, such as an expandable ring or bladder, located about a circumference of the body <b>130</b>. Attachment (or “coupling”) of the anchoring seal <b>128</b> to the body <b>130</b> may be provided by radially expanding the radially expanding member to engage and seal against an internal diameter of a central passage of the anchoring seal <b>128</b>. Detachment (or “decoupling”) of the anchoring seal <b>128</b> from the body <b>130</b> may be provided by radially retracting the radially expanding member to disengage the internal diameter of the central passage of the anchoring seal <b>128</b>. <figref idref="DRAWINGS">FIG. 5A</figref> is a diagram that illustrates a detachable anchoring seal <b>128</b> coupled to a body <b>130</b> of a SCU <b>122</b> in accordance with one or more embodiments. For example, the body <b>130</b> of the SCU <b>122</b> includes a radially expanding member <b>500</b> expanded radially outward into sealing engagement with an internal surface <b>502</b> of a central passage <b>504</b> of the detachable anchoring seal <b>128</b>. <figref idref="DRAWINGS">FIG. 5B</figref> is a diagram that illustrates the detachable anchoring seal <b>128</b> decoupled from the body <b>130</b> of a SCU <b>122</b> in accordance with one or more embodiments. For example, the body <b>130</b> of the SCU <b>122</b> includes a radially expanding member <b>500</b> retracted radially inward to disengage the internal surface <b>502</b> of the central passage <b>504</b> of the detachable anchoring seal <b>128</b>. <figref idref="DRAWINGS">FIG. 5C</figref> is a diagram that illustrates the detachable anchoring seal <b>128</b> decoupled from the body <b>130</b> of a SCU <b>122</b>, and remaining deployed in the wellbore <b>110</b>, in accordance with one or more embodiments. With the radially expanding member <b>500</b> retracted to disengage the internal surface <b>502</b> of the central passage <b>504</b> of the detachable anchoring seal <b>128</b>, the other portions of the SCU <b>122</b> (for example, including the body <b>130</b> and centralizers <b>126</b>) may be advanced along a length of the wellbore <b>110</b> through and away from the detachable anchoring seal <b>128</b>, as illustrated by the arrow, leaving the detachable anchoring seal <b>128</b> deployed in the wellbore <b>110</b>. In some embodiments, the radially expanding member <b>500</b> includes an expansion ring, such as a ring shaped inflatable bag that is disposed about a circumference of the body <b>130</b> of the SCU <b>122</b>. The expansion ring may, for example, be inflated to engage the internal surface <b>502</b> of the central passage <b>504</b> of the detachable anchoring seal <b>128</b>, and be deflated to disengage the internal surface <b>502</b> of the central passage <b>504</b> of the detachable anchoring seal <b>128</b>.

The central passage <b>504</b> of the detachable anchoring seal <b>128</b> may be a cylindrical passage defined by an internal diameter <b>506</b>. The central passage <b>502</b> of the detachable anchoring seal <b>128</b> may have a cross-sectional size that is equal to or greater than the cross-sectional size of the body <b>130</b> of the SCU <b>122</b>, and the radially expanding member <b>500</b> in a retracted position, to facilitate the removal of the SCU <b>122</b> from the detachable anchoring seal <b>128</b>. In some embodiments, to facilitate passage of down-hole components through a detachable anchoring seal <b>128</b> that remains deployed in a wellbore <b>110</b>, the central passage <b>502</b> of the detachable anchoring seal <b>128</b> may have a cross-sectional size that is equal to or greater than the cross-sectional size of the production tubing <b>118</b> in the wellbore <b>110</b>. For example, where the production tubing <b>118</b> has a minimum ID of about 4 inches (about 10 cm), the central passage <b>502</b> of the detachable anchoring seal <b>128</b> may have an ID <b>506</b> of about 4 inches (about 10 cm) or more. Thus, for example, components that can be passed through the production tubing <b>118</b> can also be passed through the central passage <b>504</b> of the non-retrievable anchoring seal <b>128</b> while it remains deployed in the wellbore <b>110</b>.

In some embodiments, an anchoring seal <b>128</b> is retrievable. A retrievable anchoring seal <b>128</b> may be designed to be retrieved from the target zone <b>124</b> of the wellbore <b>110</b> with or without the SCU <b>122</b>. For example, a retrievable anchoring seal <b>128</b> may be coupled to a SCU <b>122</b> during advancement of the SCU <b>122</b> to a target zone <b>124</b>, the SCU <b>122</b> may be deployed (for example, including deployment of the anchoring seal <b>128</b>), the SCU <b>122</b> may be operated to provide completion operations (for example, blocking breakthrough substances from entering the flow of production fluid in the wellbore <b>110</b>), the SCU <b>122</b> may be un-deployed (for example, including un-deployment of the anchoring seal <b>128</b>), and the SCU <b>122</b> (including the anchoring seal <b>128</b>) may be retrieved from the target zone <b>124</b>. As a further example, a retrievable anchoring seal <b>128</b> may be coupled to a SCU <b>122</b> during advancement of the SCU <b>122</b> to a target zone <b>124</b>, the SCU <b>122</b> may be deployed (for example, including deployment of the anchoring seal <b>128</b>), the SCU <b>122</b> may be operated to provide completion operations (for example, blocking breakthrough substances from entering the flow of production fluid in the wellbore <b>110</b>), the SCU <b>122</b> may be un-deployed (for example, including decoupling of the anchoring seal <b>128</b> from the SCU body <b>130</b> of the SCU <b>122</b>), the SCU <b>122</b> (not including the anchoring seal <b>128</b>) may be retrieved from the target zone <b>124</b>, and the anchoring seal <b>128</b> may be subsequently retrieved from the target zone <b>124</b>. A retrievable anchoring seal <b>128</b> may be advantageous, for example, in the event a device needs to be placed down-hole of the target zone <b>124</b> and removal of the SCU <b>122</b> and the anchoring seal <b>128</b> facilitates the passage of the device through the target zone <b>124</b>.

In some embodiments, an anchoring seal <b>128</b> is non-retrievable. A non-retrievable anchoring seal <b>128</b> of a SCU <b>122</b> may be designed to detach from a body <b>130</b> of a SCU <b>122</b> and to remain in the target zone <b>124</b> of the wellbore <b>110</b>, even when the remainder of the SCU <b>122</b> is retrieved from the target zone <b>124</b>. For example, a non-retrievable anchoring seal <b>128</b> may be coupled to a SCU <b>122</b> during advancement of the SCU <b>122</b> to a target zone <b>124</b>, the SCU <b>122</b> may be deployed (for example, including deployment of the anchoring seal <b>128</b>), the SCU <b>122</b> may be operated to provide completion operations (for example, blocking breakthrough substances from entering the wellbore <b>110</b>), the SCU <b>122</b> may be un-deployed (for example, including decoupling of the anchoring seal <b>128</b> from the SCU body <b>130</b> of the SCU <b>122</b>), the SCU <b>122</b> (not including the anchoring seal <b>128</b>) may be retrieved from the target zone <b>124</b>, and the anchoring seal <b>128</b> may remain deployed in the target zone <b>124</b>. In some embodiments, a non-retrievable anchoring seal <b>128</b> includes an anchoring seal <b>128</b> that takes on a hardened form and is thus not capable of being retracted (un-deployed). For example, a non-retrievable anchoring seal <b>128</b> of a SCU <b>122</b> may include an inflatable bladder that is inflated with a substance in a fluid form, such as cement or epoxy, that subsequently hardens to form a solid-rigid sealing member that extends between a body <b>130</b> of the SCU <b>122</b> and the walls of the wellbore <b>110</b>. Such a solid sealing member may provide relatively permanent, secure positioning of the anchoring seal <b>128</b> and the SCU <b>122</b> in the wellbore <b>110</b>.

In some embodiments, the SCU <b>122</b> includes an onboard (or “local”) control system <b>138</b> that controls functional operations of the SCU <b>122</b>. For example, the local control system <b>138</b> may include a local communications system <b>140</b>, a local processing system <b>142</b>, a local energy system <b>143</b>, a local sensing system <b>144</b>, a local flow control system <b>146</b>, and a positioning control system <b>147</b>. In some embodiments, the local control system <b>138</b> includes a computer system that is the same as or similar to that of computer system <b>1000</b> described with regard to at least <figref idref="DRAWINGS">FIG. 8</figref>.

In some embodiments, the local communication system <b>140</b> includes a SCU wireless transceiver <b>148</b> or a similar wireless communication circuit. The SCU wireless transceiver <b>148</b> may provide bi-directional wireless communication with other components of the system, such as the wireless down-hole transceiver <b>125</b>, the wireless transceiver <b>123</b><i>a </i>of the motive device <b>123</b>, or other SCUs <b>122</b> located in the wellbore <b>110</b>. A wireless transceiver may include, for example, an electromagnetic and/or acoustic wireless transceiver. In some embodiments, the SCU wireless transceiver <b>148</b> includes one or more wireless antennas <b>151</b>. A wireless antenna <b>151</b> may facilitate wireless communication between the SCU <b>122</b> and another device having a complementary wireless antenna. For example, a SCU <b>122</b> may include one or both of a first (or “up-hole”) antenna <b>151</b><i>a </i>disposed at an up-hole end of the SCU <b>122</b> (for example, in the last 25% of the up-hole end of the length of a body <b>130</b> of the SCU <b>122</b>) and a second (or “down-hole”) antenna <b>151</b><i>b </i>disposed the down-hole end of the SCU <b>122</b> (for example, in the last 25% of the down-hole end of the length of the body <b>130</b> of the SCU <b>122</b>). Placement of the up-hole antenna <b>151</b><i>a </i>in a SCU <b>122</b> may help to improve communication with devices located up-hole of the SCU <b>122</b>, such as the wireless down-hole transceiver <b>125</b>, the wireless transceiver <b>123</b><i>a </i>of the motive device <b>123</b>, or other SCUs <b>122</b> located up-hole of the SCU <b>122</b> in the wellbore <b>110</b>. Placement of the down-hole antenna <b>151</b><i>b </i>in a SCU <b>122</b> may help to improve communication with devices located down-hole of the SCU <b>122</b>, such as other SCUs <b>122</b> or the wireless transceiver <b>123</b><i>a </i>of the motive device <b>123</b>, located down-hole of the SCU <b>122</b> in the wellbore <b>110</b>.

In some embodiments, the local communication system <b>140</b> includes one or more SCU inductive couplers <b>152</b>. An inductive coupler may enable communication with other devices, such as other SCUs <b>122</b>, via an inductive coupling between an inductive coupler of the SCU <b>122</b> and a complementary inductive coupler of the other devices. For example, a SCU <b>122</b> may include one or both of a first (or “up-hole”) inductive coupler <b>152</b><i>a </i>disposed at an up-hole end of a body <b>130</b> of the SCU <b>122</b>, and a second (or “down-hole”) inductive coupler <b>152</b><i>b </i>disposed the down-hole end of the body <b>130</b> of the SCU <b>122</b>. Such a configuration may enable SCUs <b>122</b> to communicate with one another via inductive coupling. For example, two SCUs <b>122</b> may be assembled such that a down-hole end <b>132</b> of a body <b>130</b> of a first SCU <b>122</b> of the two SCUs <b>122</b> mates with (or otherwise abuts against) an up-hole end <b>134</b> of a body <b>130</b> of a second SCU <b>122</b> of the two SCUs <b>122</b>, and such that a down-hole inductive coupler <b>152</b><i>b </i>of the first SCU <b>122</b> aligns with an up-hole inductive coupler <b>152</b><i>a </i>of the second SCU <b>122</b>. In such an embodiment, the local communication systems <b>140</b> of the first and second SCUs <b>122</b> may communicate with one another by way of inductive coupling between the down-hole inductive coupler <b>150</b><i>b </i>of the first SCU <b>122</b> and the up-hole inductive coupler <b>152</b><i>a </i>of the second SCU <b>122</b>.

In some embodiments, the local processing system <b>142</b> of a SCU <b>122</b> includes a processor that provides processing of data, such as sensor data obtained by way of the local sensing system <b>144</b>, and controls various components of the SCU <b>122</b>. This can include controlling positioning control system <b>147</b> (for example, including deployment of the centralizers <b>126</b> and anchoring seals <b>128</b>, controlling coupling of the body <b>130</b> to detachable anchoring seals <b>128</b>), controlling operation of the local energy system <b>143</b>, controlling operation of the local sensing system <b>144</b>, controlling operation of the local flow control system <b>146</b>, and controlling operation of the local communication system <b>140</b>. In some embodiments, the local processing system includes a processor that is the same as or similar to that of processor <b>1006</b> of the computer system <b>1000</b> described with regard to at least <figref idref="DRAWINGS">FIG. 8</figref>.

In some embodiments, a local energy system <b>143</b> of a SCU <b>122</b> includes a local energy source. A local energy source may include, for example, an energy harvesting system designed to harvest energy from the down-hole environment, such as a flow energy harvester, a vibration energy harvester, or a thermal energy harvester. The local energy source may include local energy storage, such as rechargeable batteries, ultra-charge capacitors, or mechanical energy storage devices (for example, a flywheel). In some embodiments, a local energy system <b>143</b> of a SCU <b>122</b> may harvest energy from production fluids or other substances flowing through or otherwise present in a central passage <b>136</b> of the SCU <b>122</b>. For example, a local energy system <b>143</b> of a SCU <b>122</b> may include a flow energy harvester including a turbine that is disposed in a central passage <b>136</b> of a SCU body <b>130</b> of the SCU <b>122</b>, and that is operated to extract energy from production fluids flowing through the central passage <b>136</b>. The extracted energy may be used to charge a battery of the SCU <b>122</b>. The energy generated and the energy stored may be used to power functional operations of the SCU <b>122</b>.

In some embodiments, a local sensing system <b>144</b> of a SCU <b>122</b> includes sensors for detecting various down-hole conditions, such as temperature sensors, pressure sensors, flow sensors, water-cut sensors, and water saturation sensors. In some embodiments, a set of sensors may be provided to acquire measurements of conditions of the zonally isolated regions. Referring to the example SCU <b>122</b>′ of <figref idref="DRAWINGS">FIG. 2A</figref>, for example, respective first, second, third and fourth sets of sensors <b>150</b><i>a</i>, <b>150</b><i>b</i>, <b>150</b><i>c</i>, <b>150</b><i>d </i>(for example, respective sets of temperature sensors, pressure sensors, flow sensors, water-cut sensors, and water saturation sensors) may detect respective sets of conditions (for example, respective sets of temperature pressure, flow, water-cut and water saturation) in the respective first, second, third and fourth regions <b>110</b><i>a</i>, <b>110</b><i>b</i>, <b>110</b><i>c </i>and <b>110</b><i>d</i>. Referring to the example SCU <b>122</b>″ of <figref idref="DRAWINGS">FIG. 3A</figref>, for example, respective first, second, and third sets of sensors <b>150</b><i>e</i>, <b>150</b><i>f </i>and <b>150</b><i>g </i>may detect respective sets of conditions in the respective first, second, and third regions <b>110</b><i>e</i>, <b>110</b><i>f </i>and <b>110</b><i>g</i>. Referring to the example SCU <b>122</b>′″ of <figref idref="DRAWINGS">FIG. 4A</figref>, for example, respective first and second sets of sensors <b>150</b><i>h </i>and <b>150</b><i>i </i>may detect respective sets of conditions in the first and second regions <b>110</b><i>h </i>and <b>110</b><i>i. </i>

In some embodiments, a local flow control system <b>146</b> of a SCU <b>122</b> includes valves or similar flow control devices for controlling the flow of fluids from the target zone <b>124</b>, the upstream flow of production fluid from down-hole of the SCU <b>122</b> and the target zone <b>124</b>, and the downstream flow of injection fluids from up-hole of the SCU <b>122</b> and the target zone <b>124</b>. In some embodiments, the central passage <b>136</b> of an SCU <b>122</b> provides fluid communication between some of all of the zonally isolated regions created by the SCU <b>122</b>, and a local flow system <b>146</b> of the SCU <b>122</b> includes one or more valves to selectively control the flow of fluid between the zonally isolated regions and the central passage <b>136</b>. Referring to the example SCU <b>122</b>′ of <figref idref="DRAWINGS">FIG. 2A</figref>, for example, first, second, third and fourth valves <b>162</b><i>a</i>, <b>162</b><i>b</i>, <b>162</b><i>c </i>and <b>162</b><i>d </i>may control the flow of fluid into the central passage <b>136</b> from the respective first, second, third and fourth regions <b>110</b><i>a</i>, <b>110</b><i>b</i>, <b>110</b><i>c </i>and <b>110</b><i>d</i>. The first valve <b>162</b><i>a </i>and the fourth valve <b>162</b><i>d </i>may be opened, and the second valve <b>162</b><i>b </i>and the third valve <b>162</b><i>c </i>may be closed, to enable production fluid to flow upstream from the fourth region <b>110</b><i>d </i>into the first region <b>110</b><i>a</i>, while preventing breakthrough fluid in the second region <b>110</b><i>b </i>and the third region <b>110</b><i>c </i>from flowing into the production fluid and the first region <b>110</b><i>c</i>. The second region <b>110</b><i>b </i>and the third region <b>110</b><i>c </i>may be referred to as target regions of the target zone <b>124</b> in which the SCU <b>122</b>′ is deployed. Referring to the example SCU <b>122</b>″ of <figref idref="DRAWINGS">FIG. 3A</figref>, for example, first, second, and third valves <b>162</b><i>e</i>, <b>162</b><i>f </i>and <b>162</b><i>g </i>may control the flow of fluid into the central passage <b>136</b> from the respective first, second and third regions <b>110</b><i>e</i>, <b>110</b><i>f</i>, and <b>110</b><i>g</i>. The first valve <b>162</b><i>e </i>and the third valve <b>162</b><i>g </i>may be opened, and the second valve <b>162</b><i>f </i>may be closed, to enable production fluid to flow upstream from the third region <b>110</b><i>g </i>into the first region <b>110</b><i>e</i>, while preventing breakthrough fluid in the second region <b>110</b><i>f </i>from flowing into the production fluid and the first region <b>110</b><i>e</i>. The second region <b>110</b><i>f </i>may be referred to as the target region of the target zone <b>124</b> in which the SCU <b>122</b>″ is deployed. Referring to the example SCU <b>122</b>′″ of <figref idref="DRAWINGS">FIG. 4A</figref>, for example, respective first, second and third valves <b>162</b><i>h</i>, <b>162</b><i>i </i>and <b>162</b><i>j </i>may control the flow of fluid into the central passage <b>136</b> from the respective first and second regions <b>110</b><i>h </i>and <b>110</b><i>i. </i>

A valve may include, for example, a sliding sleeve, a ball valve, or similar device. Referring to the example SCU <b>122</b>″ of <figref idref="DRAWINGS">FIG. 3A</figref>, for example, the valve <b>162</b><i>b </i>may include an inflow control valve (ICV) including a tubular sleeve <b>163</b> disposed in the central passage <b>136</b> of the SCU <b>122</b>″, and disposed adjacent perforations <b>164</b> that extend radially through the body <b>130</b> of the SCU <b>122</b>″. The tubular sleeve <b>163</b> may have complementary perforations <b>166</b> that extend radially through the tubular sleeve <b>163</b>. During operation of the valve <b>162</b><i>b</i>, the sleeve <b>163</b> may be advanced (for example, rotated laterally within the central passage <b>136</b> or slid longitudinally along a length of the central passage <b>136</b>) into an opened position that includes aligning the perforations <b>166</b> of the tubular sleeve <b>163</b> with the complementary perforations <b>164</b> of the body <b>130</b> of the SCU <b>122</b>″, to define an opened path between the central passage <b>136</b> and the second region <b>110</b><i>f </i>external to the body <b>130</b> that enables the flow of substances between the central passage <b>136</b> and the second region <b>110</b><i>f</i>. The sleeve <b>163</b> may be advanced into a closed position that includes the perforations <b>166</b> of the tubular sleeve <b>163</b> and the perforations <b>164</b> of the body <b>130</b> of the SCU <b>122</b>″ being fully offset from one another, to block the flow of substances between the central passage <b>136</b> and the second region <b>110</b><i>f</i>. The sleeve <b>163</b> may be advanced into a partially opened position that includes partially aligning (or “partially offsetting”) the perforations <b>166</b> of the tubular sleeve <b>163</b> with the perforations <b>164</b> of the body <b>130</b> of the SCU <b>122</b>″ to define a partially opened path between the central passage <b>136</b> and the second region <b>110</b><i>f</i>, to enable restricted (or “throttled”) flow of substances between the passage <b>160</b> and the second region <b>110</b><i>f. </i>

In some embodiments, a positioning control system (also referred to as a “centralizer control system” or an “anchoring seal control system”) <b>147</b> of a SCU <b>122</b> includes one or more devices for controlling operations of the centralizers <b>126</b>, the anchoring seals <b>128</b> and a radially expanding member (“expansion member”) <b>500</b> of the SCU <b>122</b>. For example, the positioning control system <b>147</b> of an SCU <b>122</b> may include one more mechanical actuators that provide the motive force to move the centralizers <b>126</b> between un-deployed and deployed positions. As a further example, the positioning control system <b>147</b> of an SCU <b>122</b> may include a fluid pump that supplies fluid pressure to deploy or un-deploy one or more anchoring seals <b>128</b>. Deployment of an anchoring seal <b>128</b> may include the fluid pump pumping fluid from an on-board fluid reservoir, into an inflatable bladder of the anchoring seal <b>128</b> to inflate the bladder. Un-deployment of an anchoring seal <b>128</b> may include the fluid pump pumping fluid out of the inflatable bladder of the anchoring seal <b>128</b>, into the on-board fluid reservoir, to deflate the bladder. As a further example, the positioning control system <b>147</b> of an SCU <b>122</b> may include a fluid pump that supplies fluid pressure to deploy or un-deploy a radially expanding member <b>500</b> of the SCU <b>122</b>. Deployment of a radially expanding member <b>500</b> may include the fluid pump pumping fluid from an on-board fluid reservoir, into an inflatable bladder of the radially expanding member <b>500</b> to inflate the bladder, and to cause the bladder to expand radially into sealing contact with an internal surface <b>502</b> of a central passage <b>504</b> of the detachable anchoring seal <b>128</b>. Un-deployment of a radially expanding member <b>500</b> may include the fluid pump pumping fluid out of the inflatable bladder of the radially expanding member <b>500</b>, into the on-board fluid reservoir, to deflate the bladder, and to cause the bladder to retract radially out of sealing contact with the internal surface <b>502</b> of the central passage <b>504</b> of the detachable anchoring seal <b>128</b>.

In some embodiments, a SCU <b>122</b> is formed of one or more SCU modules (SCUMs). For example, multiple SCUMs may be assembled (for example, coupled end-to-end) to form a SCU <b>122</b> that is or can be deployed in a target zone <b>124</b>. In some embodiments, SCUMs are delivered to a target zone <b>124</b> individually or preassembled with other SCUMs. For example, multiple SCUMs may be passed through the production tubing <b>118</b> and the wellbore <b>110</b> one-by-one, and be coupled end-to-end, to form the SCU <b>122</b><i>a </i>down-hole, in the target zone <b>124</b><i>a</i>. In some embodiments, multiple SCUMs can be pre-assembled before being run down-hole to form some or all of a SCU <b>122</b> to be disposed in a target zone <b>124</b>. For example, three SCUMs may be coupled end-to-end at the surface <b>107</b>, to form the SCU <b>122</b><i>b </i>at the surface <b>107</b>, and the assembled SCU <b>122</b><i>b </i>(including the three SCUMs) may be run through the production tubing <b>118</b> and the wellbore <b>110</b> into the target zone <b>124</b><i>b</i>. If additional SCUMs are needed, the additional SCUMs can be provided in separate runs. For example, where five SCUMs are needed in the target zone <b>124</b><i>b</i>, two additional SCUMs may be run through the production tubing <b>118</b> and the wellbore <b>110</b> into the target zone <b>124</b>, and be coupled against the up-hole end of the three SCUMs already located in the target zone <b>124</b><i>b </i>of the wellbore <b>110</b> to form the SCU <b>122</b>. Thus, the SCUMs can be positioned and assembled in a modular fashion to form a modular type SCU <b>122</b> down-hole, without having to remove production tubing <b>118</b> of a well system <b>106</b>.

In some instances, it can be advantageous to run SCUMs individually, or at least with a lesser number of assembled SCUMs, as the smaller size may facilitate passage through the production tubing <b>118</b> and wellbore <b>110</b>. For example, a lesser number of assembled SCUMs may have a relatively short overall length, as compared to the fully assembled SCU <b>122</b>, that facilitates navigating relatively tight bends in the production tubing <b>118</b> and the wellbore <b>110</b>. Further, a lesser number of assembled SCUMs may have a relatively low weight, as compared to a fully assembled SCU <b>122</b>, that facilitates advancing the SCUMs through the production tubing <b>118</b> and the wellbore <b>110</b>. In some instances, it can be advantageous to run a greater number of assembled SCUMs, or even a fully assembled SCU <b>122</b>, to reduce the number of runs needed to deliver the SCU <b>122</b> to the target zone <b>124</b>. How a SCUMs of a modular SCU <b>122</b> are delivered may be based on the complexity of the well <b>108</b>, such as the size length, and trajectory of the production tubing <b>118</b> and the wellbore <b>110</b>.

<figref idref="DRAWINGS">FIG. 6A</figref> is a diagram that illustrates a modular SCU <b>170</b> formed of multiple SCUMs <b>172</b> (including SCUM <b>172</b><i>a</i>, SCUM <b>172</b><i>b </i>and SCUM <b>172</b><i>c</i>), in accordance with one or more embodiments. Each SCUM <b>172</b> may have a first (“leading” or “down-hole”) end <b>174</b> and a second (“trailing” or “up-hole”) end <b>176</b>. In some embodiments, first and second ends <b>174</b> and <b>176</b> of two respective SCUMs <b>172</b> are coupled to (or otherwise abutted against) one another to form a modular SCU <b>170</b>. Although certain embodiments are described in the context of a modular SCU <b>170</b> formed of three SCUMs <b>172</b> for the purpose of illustration, a modular SCU <b>170</b> may include any suitable number of SCUMs <b>172</b>. In some embodiments, an SCU <b>122</b> may be a modular SCU <b>170</b>. For example, the SCU <b>122</b><i>a</i>, the SCU <b>122</b><i>b </i>or the SCU <b>122</b><i>c </i>may be a modular type SCU <b>122</b>. Moreover, although the modular components of a modular SCU <b>170</b> are described as SCUMs <b>172</b> for the purpose illustration, in some embodiments, a SCUM <b>172</b> can include one of the SCUs <b>122</b> described here. For example, a modular SCU <b>122</b> may be formed of multiple SCUs <b>122</b>′ coupled end-to-end, multiple SCUs <b>122</b>″ coupled end-to-end, multiple SCUs <b>122</b>′″ coupled end-to-end, or any combination of the three coupled end-to-end. For example, <figref idref="DRAWINGS">FIGS. 6B, 6C and 6D</figref> are diagrams that illustrate example modular SCUs <b>170</b> formed of multiple SCUs <b>122</b> (SCUMs <b>172</b>) in accordance with one or more embodiments. <figref idref="DRAWINGS">FIG. 6B</figref> is a diagram that illustrates a longitudinal cross-sectioned view of an example modular SCUs <b>172</b>′ formed of multiple SCUs <b>122</b>′ (SCUMs <b>172</b>′) coupled end-to-end in accordance with one or more embodiments. <figref idref="DRAWINGS">FIG. 6C</figref> is a diagram that illustrates a longitudinal cross-sectioned view of an example modular SCU <b>170</b>″ formed of multiple SCUs <b>122</b>″ (SCUMs <b>172</b>″) coupled end-to-end in accordance with one or more embodiments. <figref idref="DRAWINGS">FIG. 6D</figref> is a diagram that illustrates a longitudinal cross-sectioned view of an example modular SCUs <b>170</b>′ formed of multiple SCUs <b>122</b>′″ (SCUMs <b>172</b>′″) coupled end-to-end in accordance with one or more embodiments.

In some embodiments, the multiple SCUMs <b>172</b> of a modular SCU <b>170</b> are operated in coordination to provide an expanded set of down-hole completion operations. Referring to the modular SCU <b>122</b> of <figref idref="DRAWINGS">FIG. 6D</figref>, for example, where three SCUs <b>122</b>′ (SCUMs <b>172</b>′) are coupled end-to-end in the target zone <b>124</b>, the first valves <b>162</b><i>h </i>and the third valves <b>162</b><i>j </i>of the three SCUs <b>122</b>′ (SCUMs <b>172</b>′″) may be opened, and the second valves <b>162</b><i>i </i>of the three SCUs <b>122</b>′ (SCUMs <b>172</b>′″) may be closed, to enable production fluid to flow upstream from a region <b>110</b><i>m </i>down-hole of the modular SCU <b>170</b>′ to a region <b>110</b><i>j </i>up-hole of the modular SCU <b>170</b>′″, and to prevent breakthrough fluid in the regions <b>110</b><i>k </i>and <b>110</b><i>l </i>from flowing into the production fluid and the regions <b>110</b><i>j </i>and <b>110</b><i>m. </i>

In some embodiments, SCUMs <b>172</b> of a modular SCU <b>170</b> are delivered to a target zone <b>124</b> individually. For example, multiple SCUMs <b>172</b> may be passed through the production tubing <b>118</b> and wellbore <b>110</b> of the well <b>108</b> one-by-one, and be coupled together end-to-end in the target zone <b>124</b> to form a modular SCU <b>170</b> down-hole. Referring to <figref idref="DRAWINGS">FIG. 6A</figref>, for example, the first SCUM <b>172</b><i>a </i>may be passed through the production tubing <b>118</b> and the wellbore <b>110</b> of the well <b>108</b>, and be disposed in target zone <b>124</b>. The second SCUM <b>172</b><i>b </i>may then be passed through the production tubing <b>118</b> and the wellbore <b>110</b> of the well <b>108</b>, and be disposed in target zone <b>124</b> such that a leading end <b>174</b> of the second SCUM <b>172</b><i>b </i>couples to a trailing end <b>176</b> of the first SCUM <b>172</b><i>a</i>. The third SCUM <b>172</b><i>b </i>may then be passed through the production tubing <b>118</b> and the wellbore <b>110</b> of the well <b>108</b>, and be disposed in target zone <b>124</b>, such that a leading end <b>174</b> of the third SCUM <b>172</b><i>b </i>couples to the trailing end <b>176</b> of the second SCUM <b>200</b><i>a</i>. In some embodiments, SCUMs <b>172</b> of a modular SCU <b>170</b> are delivered to a target zone <b>124</b> preassembled with other SCUMs <b>172</b> of the modular SCU <b>170</b>. For example, referring to <figref idref="DRAWINGS">FIG. 6A</figref>, the three SCUMs <b>172</b><i>a</i>, <b>172</b><i>b </i>and <b>172</b><i>c </i>may be assembled end-to-end at the surface <b>107</b> (for example, such that such that a leading end <b>174</b> of the second SCUM <b>172</b><i>b </i>couples to a trailing end <b>176</b> of the first SCUM <b>172</b><i>a</i>, and a leading end <b>174</b> of the third SCUM <b>172</b><i>b </i>couples to the trailing end <b>176</b> of the second SCUM <b>200</b><i>a</i>), and be run as an assembled unit through the production tubing <b>118</b> and the wellbore <b>110</b>, to the target zone <b>124</b>. In some embodiments, additional SCUMs <b>172</b> can be provided in separate runs. For example, where five SCUMs <b>172</b> are needed in the target zone <b>124</b>, two additional SCUMs <b>172</b> may be assembled at the surface <b>107</b>, and be run as an assembled unit through the production tubing <b>118</b> and the wellbore <b>110</b>, to the target zone <b>124</b>. The two additional SCUMs <b>172</b> may be assembled with (for example, coupled against an up-hole end of) the three SCUMs <b>172</b> already disposed in the target zone <b>124</b>. Thus, the SCUMs <b>172</b> can be positioned and assembled in a modular fashion to form a modular SCU <b>170</b> down-hole, without having to remove production tubing <b>118</b> from a well <b>108</b>. As noted, in some embodiments, a modular SCU <b>170</b> is run as a complete system. For example, where five SCUMs <b>172</b> are needed in a target zone <b>124</b>, five SCUMs <b>172</b> may be assembled at the surface <b>107</b>, and be run as an assembled unit through the production tubing <b>118</b> and the wellbore <b>100</b>, into the target zone <b>124</b>.

In some embodiments, each SCUMs <b>172</b> of a modular SCU <b>170</b> can communicate individually with the down-hole wireless transceiver <b>125</b>. For example, referring to the modular SCU <b>170</b>″ of <figref idref="DRAWINGS">FIG. 6C</figref> (formed of multiple SCUs <b>122</b>″) (SCUMs <b>172</b><i>a</i>″, <b>172</b><i>b</i>″ and <b>172</b><i>c</i>″) coupled end-to-end, the wireless transceiver <b>148</b> of each of the first SCUM <b>172</b><i>a</i>″, the second SCUM <b>1720</b><i>b</i>″ and the third SCUM <b>172</b><i>c</i>″ may communicate directly with the down-hole wireless transceiver <b>125</b> by way of its up-hole antenna <b>151</b><i>a</i>. In some embodiments, the SCUMs <b>172</b> of a modular SCU <b>170</b> can communicate with one another. For example, referring again to the modular SCU <b>170</b>″ of <figref idref="DRAWINGS">FIG. 6C</figref>, the first SCUM <b>172</b><i>a</i>″ may communicate with the second SCUM <b>172</b><i>b</i>″ by way of their respective local communication systems <b>140</b>. This can include, for example, communication by way of wireless communication between their respective wireless transceivers <b>148</b> or by way of inductive coupling between them (for example, by way of inductive coupling between the up-hole and down-hole inductive couplers <b>152</b><i>a </i>and <b>152</b><i>b </i>of the second and first SCUMs <b>172</b><i>b</i>″ and <b>172</b><i>a</i>″, respectively). The first SCUM <b>172</b><i>a</i>″ may communicate with the third SCUM <b>172</b><i>c</i>″ by way of their respective local communication systems <b>140</b>. This can include, for example, by way of wireless communication between their respective wireless transceivers <b>148</b> or by way of inductive coupling between them (for example, by way of inductive coupling between the up-hole and down-hole inductive couplers <b>152</b><i>a </i>and <b>152</b><i>b </i>of the third and second SCUMs <b>172</b><i>c</i>″ and <b>172</b><i>b</i>″, respectively, and inductive coupling between the up-hole and down-hole inductive couplers <b>152</b><i>a </i>and <b>152</b><i>b </i>of the second and first SCUMs <b>172</b><i>b</i>″ and <b>172</b><i>a</i>″, respectively).

In some embodiments, the SCUMs <b>172</b> of a modular SCU <b>170</b> may have coordinated communication with the down-hole wireless transceiver <b>125</b>. An up-hole most SCUM <b>172</b> of a modular SCU <b>170</b> may communicate directly with devices up-hole of the SCU <b>170</b>, such as the down-hole wireless transceiver <b>125</b>, and a down-hole most SCUM <b>172</b> of a modular SCU <b>170</b> may communicate directly with devices down-hole of the SCU <b>170</b>. For example, referring again to the modular SCU <b>170</b>″ of <figref idref="DRAWINGS">FIG. 6C</figref>, the wireless transceiver <b>148</b> of the first SCUM <b>172</b><i>a</i>″ may communicate directly with the down-hole wireless transceiver <b>125</b> by way of its first antenna <b>151</b><i>a</i>, and act an intermediary to relay communications between the down-hole wireless transceiver <b>125</b> and the second and third SCUMs <b>172</b><i>b</i>″ and <b>172</b><i>c</i>″. Further, the wireless transceiver <b>148</b> of the third SCUM <b>172</b><i>b</i>″ may communicate directly with a wireless transceiver <b>125</b> of a device, such as another SCU <b>122</b>, located down-hole of the modular SCU <b>170</b> by way of its second antenna <b>151</b><i>b</i>, and act an intermediary to relay communications between the device located down-hole of the modular SCU <b>170</b> and the first and second SCUMs <b>172</b><i>a</i>″ and <b>172</b><i>b″. </i>

<figref idref="DRAWINGS">FIG. 7</figref> is a flowchart that illustrates a method <b>700</b> of operating a well using a thru-tubing completion system employing SCUs in accordance with one or more embodiments. The method <b>700</b> may generally include installing production tubing in a well (block <b>702</b>), installing a SCU in a target zone of the well by way of the production tubing (block <b>704</b>), conducting production operations using the SCU (block <b>706</b>), and repositioning the SCU (block <b>708</b>).

In some embodiments, installing production tubing in a well (block <b>402</b>) includes installing production tubing in the wellbore of a well. For example, installing production tubing in a well may include installing the production tubing <b>118</b> in the wellbore <b>110</b> of the well <b>108</b>. In some embodiments, installing production tubing includes installing a down-hole wireless transceiver at the end of the production tubing. For example, installing the production tubing <b>118</b> may include installing the down-hole wireless transceiver <b>125</b> within about 20 feet (about 6 meters) of the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b>.

In some embodiments, installing a SCU in a target zone of the well by way of the production tubing (block <b>404</b>) includes installing a SCU <b>122</b> in a target zone <b>124</b> of the well <b>108</b> by way of the production tubing <b>118</b> and an intervening portion of the wellbore <b>110</b> of the well <b>108</b>. For example, installing a SCU in a target zone of the well by way of the production tubing may include passing the SCU <b>122</b><i>a </i>through and interior of the production tubing <b>118</b> and the interior of the intervening portion of the wellbore <b>110</b>, located between the down-hole end <b>118</b><i>a </i>of the production tubing <b>118</b> and the target zone <b>124</b><i>a</i>, to position the SCU <b>122</b><i>a </i>in the target zone <b>124</b><i>a</i>. In some embodiments, a SCU <b>122</b> is advanced through the production tubing <b>118</b> or the wellbore <b>110</b>, into the target zone <b>124</b>, by way of a motive force (for example, pushing and pulling) provided by the positioning device <b>123</b>. In some embodiments, installing a SCU <b>122</b> in a target zone <b>124</b> includes deploying positioning devices to secure the SCU <b>122</b> in the target zone <b>124</b> or to provide zonal fluid isolation of regions in the target zone <b>124</b>. For example, installing the SCU <b>122</b><i>a </i>in the target zone <b>124</b><i>a </i>may include deploying one or more centralizers <b>126</b> of the SCU <b>122</b><i>a </i>to center the SCU <b>122</b><i>a </i>in the wellbore <b>110</b>, and then deploying one or more anchoring seals <b>128</b> of the SCU <b>122</b><i>a </i>to secure the SCU <b>122</b><i>a </i>in the target zone <b>124</b><i>a </i>and create a fluid seal between a body <b>130</b> of the SCU <b>122</b><i>a </i>the walls of the target zone <b>124</b><i>a </i>of the wellbore to provide zonal fluid isolation of a region in the target zone <b>124</b><i>a</i>. <figref idref="DRAWINGS">FIGS. 2A, 3A and 4A</figref> illustrate example SCUs <b>122</b>, including SCUs <b>122</b>′, <b>122</b>″ and <b>122</b>′″, installed in respective target zones <b>124</b> of a wellbore <b>110</b>.

In some embodiments, installing a SCU in a target zone of the well by way of the production tubing includes installing a modular type SCU. For example, referring to <figref idref="DRAWINGS">FIG. 6A</figref>, three SCUMs <b>172</b><i>a</i>, <b>172</b><i>b</i>, and <b>172</b><i>c </i>may be passed though the production tubing <b>118</b> and installed in the target region <b>124</b> to provide the modular SCU <b>172</b> installed in the target region <b>124</b>. As described, the SCUMs <b>172</b> may be delivered to the target zone <b>124</b> individually or together with other SCUMs <b>172</b>. For example, multiple SCUMs <b>172</b> may be passed through the production tubing <b>118</b> of the well <b>108</b>, one-by-one, and be coupled together end-to-end in the target zone <b>124</b> to form the modular SCU <b>170</b> down-hole. As a further example, multiple SCUMs <b>172</b> may be pre-assembled before being run down-hole to form some or all of a modular SCU <b>170</b> disposed in a target zone <b>124</b>. <figref idref="DRAWINGS">FIGS. 6B, 6C and 6D</figref> are diagrams that illustrate example modular SCUs <b>170</b>, including modular SCUs <b>170</b>′, <b>170</b>″ and <b>170</b>′, in accordance with one or more embodiments.

In some embodiments, conducting production operations using the SCU (block <b>406</b>) includes operating the SCU to provide various functional productions operations. For example, conducting production operations using a SCU can include operating valves of an installed SCU <b>122</b> to regulate production flow and acquiring measurements of down-hole conditions. In some embodiments, conducting production operations using the SCU includes operating the valves of a SCU <b>122</b> to provide a desired level of zonal isolation. Referring to <figref idref="DRAWINGS">FIG. 2A</figref>, for example, first, second, third and fourth valves <b>162</b><i>a</i>, <b>162</b><i>b</i>, <b>162</b><i>c </i>and <b>162</b><i>d </i>may be operated control the flow of fluid into the passage <b>136</b> of the SCU <b>122</b>′ from the respective first, second, third and fourth regions <b>110</b><i>a</i>, <b>110</b><i>b</i>, <b>110</b><i>c </i>and <b>110</b><i>d</i>. Referring to the example SCU <b>122</b>″ of <figref idref="DRAWINGS">FIG. 3A</figref>, for example, first, second, and third valves <b>162</b><i>e</i>, <b>162</b><i>f </i>and <b>162</b><i>g </i>may be operated to control the flow of fluid into the passage <b>136</b> of the SCU <b>122</b>″ from the respective first, second and third regions <b>110</b><i>e</i>, <b>110</b><i>f</i>, and <b>110</b><i>g</i>. Referring to the example SCU <b>122</b>′″ of <figref idref="DRAWINGS">FIG. 4A</figref>, for example, respective first, second and third valves <b>162</b><i>h</i>, <b>162</b><i>i </i>and <b>162</b><i>j </i>may be operated to control the flow of fluid into the passage <b>136</b> of the SCU <b>122</b>′″ from the respective first and second regions <b>110</b><i>h </i>and <b>110</b><i>i. </i>

In some embodiments, conducting production operations using the SCU includes monitoring down-hole conditions using the SCU. For example, conducting production operations using a SCU may include monitoring the various regions using sensors of an installed SCU <b>122</b>. Referring to the example SCU <b>122</b>′ of <figref idref="DRAWINGS">FIG. 2A</figref>, for example, respective first, second, third and fourth sets of sensors <b>150</b><i>a</i>, <b>150</b><i>b</i>, <b>150</b><i>c</i>, <b>150</b><i>d </i>may detect respective sets of conditions of the respective first, second, third and fourth regions <b>110</b><i>a</i>, <b>110</b><i>b</i>, <b>110</b><i>c </i>and <b>110</b><i>d</i>. Referring to the example SCU <b>122</b>″ of <figref idref="DRAWINGS">FIG. 3A</figref>, for example, respective first, second, and third sets of sensors <b>150</b><i>e</i>, <b>150</b><i>f</i>, and <b>150</b><i>g </i>may detect respective sets of conditions of the respective first, second and third regions <b>110</b><i>e</i>, <b>110</b><i>f</i>, and <b>110</b><i>g</i>. Referring to the example SCU <b>122</b>′″ of <figref idref="DRAWINGS">FIG. 4A</figref>, for example, respective first, second, and third sets of sensors <b>150</b><i>h </i>and <b>150</b><i>i </i>may detect respective sets of conditions of the respective first and second regions <b>110</b><i>h </i>and <b>110</b><i>i</i>. Sensed data indicative of the sensed conditions may be processed locally (for example, by the local processing system <b>142</b>) to generate processed sensor data, and the processed sensor data may be transmitted to the surface control unit <b>109</b><i>a </i>(for example, by way of the SCU wireless transmitter <b>148</b> and the down-hole wireless transmitter <b>125</b>) for further processing. In some embodiments, the raw sensed data may be transmitted to the surface control unit <b>109</b><i>a. </i>

In some embodiments, repositioning the SCU (block <b>408</b>) includes removing the SCU from the well by way of the production tubing. For example, if all of the anchoring seals <b>128</b> of the SCU <b>122</b><i>a </i>are retrievable, repositioning the SCU <b>122</b><i>a </i>from the target zone <b>124</b><i>a </i>may include un-deploying the anchoring seals <b>128</b> and centralizers <b>126</b> of the SCU <b>122</b><i>a</i>, and removing the SCU <b>122</b><i>a </i>(including the retrievable anchoring seals <b>128</b>) from the target zone <b>124</b><i>a</i>, through the wellbore <b>110</b> and the production tubing <b>118</b>. As a further example, if some of the anchoring seals <b>128</b> of the SCU <b>122</b><i>b </i>are detachable, repositioning the SCU <b>122</b><i>b </i>from the target zone <b>124</b><i>b </i>may include un-deploying the centralizers <b>126</b> and any retrievable anchoring seals <b>128</b>, detaching the detachable anchoring seals <b>128</b> from the body <b>130</b> of the SCU <b>122</b><i>b</i>, and removing the SCU <b>122</b><i>b </i>(except for the detached anchoring seals <b>128</b>) from the target zone <b>124</b><i>b</i>, through the wellbore <b>110</b> and the production tubing <b>118</b>. In such an embodiment, the detached anchoring seals <b>128</b> may remain fixed in the target zone <b>124</b><i>b</i>. In some embodiments, repositioning a SCU <b>122</b> includes moving the SCU <b>122</b> within the wellbore <b>110</b>, without returning the SCU <b>122</b> to the surface <b>107</b>. For example, if all of the anchoring seals <b>128</b> of the SCU <b>122</b><i>a </i>are retrievable, un-installing the SCU <b>122</b><i>a </i>from the target zone <b>124</b><i>a </i>may include un-deploying the anchoring seals <b>128</b> and centralizers <b>126</b> of the SCU <b>122</b><i>a</i>, and moving the SCU <b>122</b><i>a </i>(including the retrievable anchoring seals <b>128</b>) through the wellbore <b>110</b>, from the target zone <b>124</b><i>a </i>to the target zone <b>124</b><i>c</i>. The SCU <b>122</b><i>a </i>may be redeployed in the target zone <b>124</b><i>c </i>to provide completion operations in the target zone <b>124</b><i>c</i>. In some embodiments, a SCU <b>122</b> is repositioned using a positioning device <b>123</b>, such as a tractor, to provide motive force (for example, pulling or pushing) to advance the SCU <b>122</b> through some or all of the wellbore <b>110</b> and the production tubing <b>118</b>.

Such embodiments of a well system employing SCUs can provide an on-demand and modular completion solution that can be employed without the time and costs traditionally associated with workover procedures that require removing production tubing. For example, instead of having to bring in a workover rig to remove the production tubing string to provide access for working over a targeted zone in a wellbore, a well operator can simply pass a SCU through the production tubing into position within the target zone of the wellbore to provide the needed workover operations. This can facilitate conducting well completion operations on-demand, as conditions dictate. Moreover, the ability to install different SCUs in different target zones provide a flexible solution that can be customized for a variety of down-hole conditions. For example, different combinations and types of SCUs and SCUMs can be installed, retrieved, and repositioned as conditions dictate. Thus, embodiments of the TTCS may provide a flexible, cost and time effective completion solution that addresses ever changing well conditions and production goals.

<figref idref="DRAWINGS">FIG. 8</figref> is a diagram that illustrates an example computer system <b>1000</b> in accordance with one or more embodiments. In some embodiments, the system <b>1000</b> may be a programmable logic controller (PLC). The system <b>1000</b> may include a memory <b>1004</b>, a processor <b>1006</b>, and an input/output (I/O) interface <b>1008</b>. The memory <b>1004</b> may include non-volatile memory (for example, flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)), volatile memory (for example, random access memory (RAM), static random access memory (SRAM), synchronous dynamic RAM (SDRAM)), bulk storage memory (for example, CD-ROM and/or DVD-ROM, hard drives), and/or the like. The memory <b>1004</b> may include a non-transitory computer-readable storage medium storing program instructions <b>1010</b>. The program instructions <b>1010</b> may include program modules <b>1012</b> that are executable by a computer processor (for example, the processor <b>1006</b>) to cause the functional operations described here, including those described with regard to the surface control system <b>109</b><i>a</i>, the local control system <b>138</b>, and the method <b>700</b>.

The processor <b>1006</b> may be any suitable processor capable of executing program instructions. The processor <b>1006</b> may include a central processing unit (CPU) that carries out program instructions (for example, the program instructions of the program module(s) <b>1012</b>) to perform the arithmetical, logical, and input/output operations described herein. The processor <b>1006</b> may include one or more processors. The I/O interface <b>1008</b> may provide an interface for communication with one or more I/O devices <b>1014</b>, such as a joystick, a computer mouse, a keyboard, a display screen (for example, an electronic display for displaying a graphical user interface (GUI)), or the like. The I/O devices <b>1014</b> may include one or more of the user input devices. The I/O devices <b>1014</b> may be connected to the I/O interface <b>1008</b> by way of a wired (for example, Industrial Ethernet) or a wireless (for example, Wi-Fi) connection. The I/O interface <b>1008</b> may provide an interface for communication with one or more external devices <b>1016</b>, such as other computers, networks, and/or the like. In some embodiments, the I/O interface <b>1008</b> may include an antenna, a transceiver, and/or the like. In some embodiments, the external devices <b>1016</b> may include a tractor, sensors, centralizers, anchoring seals, and/or the like.

Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the embodiments. It is to be understood that the forms of the embodiments shown and described here are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described here, parts and processes may be reversed or omitted, and certain features of the embodiments may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the embodiments. Changes may be made in the elements described here without departing from the spirit and scope of the embodiments as described in the following claims. Headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description.

It will be appreciated that the processes and methods described here are example embodiments of processes and methods that may be employed in accordance with the techniques described. The processes and methods may be modified to facilitate variations of their implementation and use. The order of the processes and methods and the operations provided may be changed, and various elements may be added, reordered, combined, omitted, modified, etc. Portions of the processes and methods may be implemented in software, hardware, or a combination thereof. Some or all of the portions of the processes and methods may be implemented by one or more of the processors, modules, or applications described here.

As used throughout this application, the word “may” is used in a permissive sense (such as, meaning having the potential to), rather than the mandatory sense (such as, meaning must). The words “include,” “including,” and “includes” mean including, but not limited to. As used throughout this application, the singular forms “a”, “an,” and “the” include plural referents unless the content clearly indicates otherwise. Thus, for example, reference to “an element” may include a combination of two or more elements. As used throughout this application, the phrase “based on” does not limit the associated operation to being solely based on a particular item. Thus, for example, processing “based on” data A may include processing based at least in part on data A and based at least in part on data B unless the content clearly indicates otherwise. As used throughout this application, the term “from” does not limit the associated operation to being directly from. Thus, for example, receiving an item “from” an entity may include receiving an item directly from the entity or indirectly from the entity (for example, by way of an intermediary entity). Unless specifically stated otherwise, as apparent from the discussion, it is appreciated that throughout this specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” or the like refer to actions or processes of a specific apparatus, such as a special purpose computer or a similar special purpose electronic processing/computing device. In the context of this specification, a special purpose computer or a similar special purpose electronic processing/computing device is capable of manipulating or transforming signals, typically represented as physical, electronic or magnetic quantities within memories, registers, or other information storage devices, transmission devices, or display devices of the special purpose computer or similar special purpose electronic processing/computing device.